{"id":9,"date":"2008-05-06T14:07:24","date_gmt":"2008-05-06T12:07:24","guid":{"rendered":"http:\/\/oktay.com\/wp\/wordpress\/?page_id=9"},"modified":"2008-05-06T14:14:25","modified_gmt":"2008-05-06T12:14:25","slug":"aliens-bash-tutorial","status":"publish","type":"page","link":"https:\/\/wp.oktay.com\/?page_id=9","title":{"rendered":"aliens bash tutorial"},"content":{"rendered":"

original link: http:\/\/subsignal.org\/doc\/AliensBashTutorial.html<\/a>
\n=========================== Aliens Bash Tutorial ==============================
\n————— Written by Billy Wideling <-> alien@koping.net<\/a> —————-
\n===============================================================================<\/p>\n

First you probably need to read a UNIX command bible to really understand this
\ntutorial, but I will try to make it as clear as possible, there is about
\n100-150 UNIX commands explained later in this tutorial.
\nYou are to have some UNIX experance before starting on this tutorial, so
\nif you feel that you have UNIX\/Linux experance feel free to start to learn
\nhere.
\nWhat I included here is general shell scripting, most common other things
\nand some UNIX commands.
\nHere’s the most common shell types:<\/p>\n

bash\u00a0 = Bourne again shell
\nsh\u00a0\u00a0\u00a0 = shell
\ncsh\u00a0\u00a0 = C shell
\ntcsh\u00a0 = Tenex C shell (not tab-completion-extended C shell)
\ntclsh = Tcl shell
\nksh\u00a0\u00a0 = korn shell
\nash\u00a0\u00a0 = a shell
\nbsh\u00a0\u00a0 = bourne shell ? (in most Linux distributions it’s a link to \/bin\/ash)
\nzsh\u00a0\u00a0 = the Z shell (it’s what it’s manual page tells about it .. :\/ )<\/p>\n

===============================================================================
\n1 – What you already know. (should know)
\n===============================================================================<\/p>\n

Here we go, bash scripting is nothing more then combining lots of UNIX commands
\nto do things for you, you can even make simple games in bash
\n(just UNIX commands) or as in normal cases, batch files to control things
\nin your computer.<\/p>\n

There is a variety of easyer and harder examples in the beginning of this
\ntutorial, I’ve done it this way to make it easier for people to get the
\ngeneral picture, so they will get more of the “aha!” experiences in the later
\nchapters of this tutorial.<\/p>\n

What bash or any scripting language does is to call for premade programs
\nthat lives in your computer.
\nSo when you write a command in a script you are calling a command that is
\na part of the system.
\nThat is why this tutorial will be just as much a Linux and UNIX tutorial
\nas a shell scripting tutorial.<\/p>\n

I will however not take up much about The X Windows System in this
\ntutorial, for the simple reason that a Window Manager does nothing else
\nthen display programs.<\/p>\n

This means that a Window Manager is like a graphical shell for the system.
\nYou can do all in this tutorial from any terminal emulator in a Linux
\nGraphical Enviorment (The X Windows System).
\nA terminal emulator would be such as: Eterm, xterm, axvt, rxvt, kterm etc.
\nA terminal emulator let’s you get up a terminal with a command prompt
\nin a graphical window.<\/p>\n

——————————————————————————-<\/p>\n

Shell command separator\/control characters:<\/p>\n

|\u00a0 = pipe will take the first commands stdout as the second commands stdin.
\n|| = OR if first command is false, it will take the second.
\n|= = OR IS (mostly used in if statements)
\n&& = AND if first command is true, it will execute the second one.
\n!\u00a0 = NOT (mostly used in if and test statements), but as a shell-command
\n\u00a0\u00a0\u00a0\u00a0 it opens a shell to run the command (ex. `! echo foo`)
\n!= = NOT IS (mostly used in if statements)
\n!$ = last commands last argument
\n!! = repeat last command
\n=\u00a0 = IS (mostly used in if statements)
\n;\u00a0 = will separate 2 commands as if they were written on separate command lines
\n;; = end of a case function in a case statement. (see `case` further down)
\n$\u00a0 = prefix to a variable like “$myvar”
\n$! = PID of the last child process.
\n$$ = PID of current process (PID == Process ID)
\n$0 = Shows program that owns the current process.
\n$1 = First agument supplied after the program\/function on execution.
\n$2 = Second agument supplied after the program\/function on execution. ($3 etc.)
\n$# = Shows the number of arguments.
\n$? = Any argument (good to use in `if` statements)
\n$- = current option flags (I never ever had to use this one)
\n$_ = Last argument\/Command
\n$* = All arguments
\n$@ = All arguments
\n#\u00a0 = remmed line, anything on a line after “#” will be overlooked by the script
\n{\u00a0 = start braces (starts a function)
\n}\u00a0 = end braces\u00a0\u00a0 (ends a function)
\n[\u00a0 = start bracket (multiple-argument specifiers)
\n]\u00a0 = end bracket (multiple-argument specifiers)
\n@\u00a0 = $@ is equivalent to “$1” “$2″ etc. (all arguments)
\n*\u00a0 = wild card (* can substitute any number of characters)
\n?\u00a0 = wild card (? can substitute any single character)
\n”\u00a0 = quote
\n‘\u00a0 = precise quote. (Will even include “‘s in the quote)
\n`\u00a0 = command quote. (variable=`ls -la` doing $variable will show the dir list)
\n.\u00a0 = dot will read and execute commands from a file, ( . .bashrc )
\n&\u00a0 = and. as suffix to executed file makes it go to the background(.\/program &)
\n0> = stdin stream director (I never seen this used in any script)
\n1> = stdout stream director (standard output)
\n2> = stderr stream director (standard error output)
\n%\u00a0 = job character, %1 = fg job 1, %2 = fg job 2, etc.
\n>> = stream director append to a file
\n<< = stdin stream director. (cat > file << EOF ; anything ; EOF)
\n>\u00a0 = stream director that will start at the top of the file
\n\u00a0\u00a0\u00a0 (in if statements < and > may be used as greater-then
\n\u00a0\u00a0\u00a0 and lesser-then, as: if [ “$1” >= “2” ])
\n\\\u00a0 = back-slash, takes away any special meaning with a character,
\n\u00a0\u00a0\u00a0\u00a0 \\$var will not be treated as a variable.
\n\u00a0\u00a0\u00a0\u00a0 (and a new line will not be treated as a new line)
\n\u00a0\u00a0\u00a0\u00a0 Also a \\ before a command, removes any alias on the command as: \\rm
\n>& = stream director to stream director, ie. echo “a” 1>\/dev\/null 2>&1
\n\u00a0\u00a0\u00a0\u00a0 this directs 2> to the same place as 1><\/p>\n

——————————————————————————-<\/p>\n

Here is the basic UNIX or rather Linux directory structur:<\/p>\n

\u00a0\u00a0\u00a0 \/ (system root)
\n\u00a0_______________________________|____________________________________
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |
\nbin\/ boot\/ dev\/ etc\/ home\/ lib\/ lost+found\/ proc\/ root\/ sbin\/ usr\/ var\/
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |-> various
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |-> Read later..
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |-> Superuser Binarys
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |-> User roots home dir
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> system info etc.
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> Orphan files (look here after crashes)
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |-> System \/ programming librarys
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |-> Contains the user accounts home directorys
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |-> System configuration files.
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |-> Devices
\n\u00a0|\u00a0\u00a0\u00a0 |
\n\u00a0|\u00a0\u00a0\u00a0 |-> The kernel and kernel maps.
\n\u00a0|
\n\u00a0|-> Executeble files. (binarys)<\/p>\n

The \/usr directory contains a whole lot of things, mainly user accesseble
\nthings, like binarys in \/usr\/local\/bin\/ and \/usr\/bin\/ also librarys
\nin \/usr\/lib\/ and \/usr\/local\/lib\/.
\nThe kenrel source should also be under \/usr, in \/usr\/src\/linux\/
\nBut more about that later.<\/p>\n

——————————————————————————-<\/p>\n

Here’s an example of the following files locations:<\/p>\n

\/dev\/null
\n\/dev\/fd0
\n\/etc\/passwd
\n\/home\/alien\/.profile
\n\/usr\/local\/bin\/BitchX<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/
\n\u00a0_______________________________|____________________________________
\n\u00a0|\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |
\nbin\/ boot\/ dev\/ etc\/ home\/ lib\/ lost+found\/ proc\/ root\/ sbin\/ usr\/ var\/
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0 alien\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 local\/
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |-> .profile\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 |-> passwd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 bin\/
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> null\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> BitchX
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> fd0<\/p>\n

——————————————————————————-<\/p>\n

And a final example that’s a bit more stripped, just incase you are really
\nnew to computers.
\nHere following files locations:<\/p>\n

\/dev\/null
\n\/dev\/audio
\n\/dev\/hda1
\n\/etc\/passwd
\n\/etc\/shadow
\n\/home\/alien\/.profile
\n\/home\/alien\/tmp\/somefile
\n\/home\/user\/.bash_profile
\n\/usr\/local\/bin\/BitchX
\n\/sbin\/shutdown<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/
\n\u00a0 _____________________________|_____________________________
\n\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0dev\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 etc\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 home\/—–\u00a0\u00a0\u00a0 usr\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 sbin\/
\n\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0 |-> null\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0 local\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> shutdown
\n\u00a0 |-> audio\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0 |-> hda1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0 bin\/
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> passwd\u00a0 alien\/\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> shadow\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0 user\/\u00a0 |-> BitchX
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |\u00a0\u00a0\u00a0\u00a0\u00a0 |-> .bash_profile
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> .profile
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 tmp\/
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |-> somefile<\/p>\n

——————————————————————————-<\/p>\n

This is the same structure as on any Operating System that uses directorys,
\nThough some Operating Systems may call the \/ directory C: and some other
\nmay call it HD etc.
\nand ofcorse some of the directory names in Linux\/UNIX are UNIX specific.<\/p>\n

No further explanation should be nessesary.<\/p>\n

After reading this tutorial, brows around the system and try to learn
\nwhat all the files does, just dont remove any files you didnt put there
\nuntil your ABSOLUTLEY sure of what you are doing.<\/p>\n

——————————————————————————-<\/p>\n

Here’s a few UNIX commands just for illustration:<\/p>\n

echo
\n======
\n\u00a0echo will *echo* anything you add to it like this:<\/p>\n

\u00a0alien:~$ echo “blah”
\n\u00a0blah
\n\u00a0alien:~$<\/p>\n

\u00a0To get it to echo without a new line add the suffix -n
\n\u00a0like this:<\/p>\n

\u00a0alien:~$ echo -n “blah ”
\n\u00a0blah alien:~$<\/p>\n

\u00a0I’ll get back to why you want to do “-n” sometimes in a while.<\/p>\n

read
\n======
\n\u00a0read will read from the keyboard (stdin) and save it as a variable
\n\u00a0the variable name goes after the read command, like this:<\/p>\n

\u00a0alien:~$ read myvar
\n\u00a0<here I type say “blah”>
\n\u00a0alien:~$ echo $myvar
\n\u00a0blah
\n\u00a0alien:~$<\/p>\n

\u00a0To combine these two commands (echo and read) in a small script
\n\u00a0line, it can look like this:<\/p>\n

\u00a0alien:~$ echo -n “password: ” ; read pass ; echo “Your pass is $pass”
\n\u00a0password: <here I type “mypass”>
\n\u00a0Your pass is mypass
\n\u00a0alien:~$<\/p>\n

\u00a0Get the basic idea ?<\/p>\n

——————————————————————————-<\/p>\n

Anyway, here are some commands that you should know before moving on with this
\ntutorial –
\n[*] after == important to know.
\n[X] after == very basics will do.<\/p>\n

ls [*]\u00a0\u00a0\u00a0\u00a0 Ex: ls -la\u00a0 Long directory listing.
\necho [*] Ex: echo “foo”\u00a0 Does what it says.
\ncat [*] Ex: cat \/etc\/passwd Dump out the content of a file.
\nless [X] Ex: less \/etc\/passwd Scroll up and down in a file (q = exit)
\nhead [X] Ex: head -5 \/etc\/passwd Get the 5 (-5) first lines of a file.
\ntail [X] Ex: tail -7 \/etc\/passwd Get the 7 (-7) last lines of a file.
\ngrep [*] Ex: grep x \/etc\/issue\u00a0\u00a0 Dump lines containing x from \/etc\/issue
\nchmod [*] Ex: chmod a+x file Give everyone executable rights to file
\nchown [X] Ex: chown root file Change owner of file to root.<\/p>\n

(cd\u00a0\u00a0\u00a0\u00a0 [-]\u00a0\u00a0\u00a0\u00a0 Ex: cd \/etc\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Change Directory to \/etc)<\/p>\n

Some applications you need to know how to operate (basics will do) :<\/p>\n

any text editor (preferably emacs or vi – they are explaind last in this file)
\ntelnet\u00a0 Ex: telnet 127.0.0.1 Opens a connection to IP 127.0.0.1
\nlynx\u00a0 Ex: lynx http:\/\/foo.bar<\/a> A command line based web browser.
\nftp (ncftp) Ex: ncftp ftp:\/\/foo.bar<\/a> A command line based ftp client.
\nssh\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Ex: ssh 127.0.0.1 Opens a secure connection to 127.0.0.1<\/p>\n

These are all explained fully later in this tutorial.<\/p>\n

——————————————————————————-<\/p>\n

Now don’t sit there and ask yourself how’s going to teach you the commands
\nor applications I just listed here above. use the manual pages.
\nlike this:<\/p>\n

man echo<\/p>\n

that will get you the full manual on the command echo \ud83d\ude42
\nman works the same way with applications that you have the manual pages for.<\/p>\n

To get out of the manual page just press the letter “q”.
\n“q” quits it and bet’s you back to the command line prompt.
\nman uses all the normal “less” commands.<\/p>\n

Or read further down in this tutorial in the basic Linux\/UNIX commands and
\noperations section (8).<\/p>\n

——————————————————————————-<\/p>\n

The key to shell scripting just as with any programming language\/Operating
\nSystem is to REALLY understand what you are doing, so do read this file
\nmore then once, and don’t read it to fast.
\nTake your time and let it sink in, so you know what it’s all about,
\nand do take time to read manual pages and do some playing with the commands
\nso you learn them.<\/p>\n

Now that should be enough of what you *should* know before starting to learn
\nUNIX shell scripting.<\/p>\n

So here we go…….<\/p>\n

===============================================================================
\n2 – Where to start
\n===============================================================================<\/p>\n

You should always start with very simple scripts that you really don’t have
\nany practical use for but still *could* be of practical use =)<\/p>\n

As for first let’s make what we already know to a *real* executable script.
\nOpen a text editor (name the file myscript.sh) and type this:<\/p>\n

#!\/bin\/bash<\/p>\n

echo -n “password: ”
\nread pass
\necho “Your pass is $pass”<\/p>\n

save & exit — then do this command: chmod u+x myscript.sh
\nThen we can execute it:<\/p>\n

\u00a0alien:~$ .\/myscript.sh
\n\u00a0password: <type what you want>
\n\u00a0Your pass is <what you typed>
\n\u00a0alien:~$<\/p>\n

The “#!\/bin\/bash” at the start of the file is to let the script know what
\nshell type it should use.<\/p>\n

The “chmod u+x myscript.sh” is to make it executable.
\n(change-mode user+execute-right-on myscript.sh) ….. read the manual pages
\non chmod for more info on it =)<\/p>\n

——————————————————————————-<\/p>\n

Take alot of time to play around in your system, open files, figure out
\nwhat they do (but don’t edit or remove them).<\/p>\n

Take time also to learn some good text editor, that’s important.
\nLearn, emacs or vi, those are by most people considerd the absolutly best,
\nbut jed, joe, elvis, pico or any simple editor like that will do
\njust fine for now.<\/p>\n

emacs and vi are explained later in this tutorial.<\/p>\n

——————————————————————————-<\/p>\n

Another thing before moving on is that you can export a variable from a
\nscript.<\/p>\n

Say that you have the variable “$var” in a script and want to export
\nit to the system for use with some other script or something, you can
\ndo: export var<\/p>\n

Like this little script:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

VAR=”10″
\nexport VAR<\/p>\n

——————————————————————————-<\/p>\n

Note: VAR=”10″ can not be written as VAR = “10”, since it’s
\n\u00a0\u00a0\u00a0\u00a0\u00a0 ‘whitespace-sensetive’.<\/p>\n

——————————————————————————-<\/p>\n

But more to how to make scripts in a second, I just thought that this would
\nbe a good time to enlighten you about this.<\/p>\n

So here we go ….<\/p>\n

===============================================================================
\n3 – Beginning techniques.
\n===============================================================================<\/p>\n

First off I’m going to show how to count in bash or how to use your command
\nline as a calculator, which is really easy and useful.<\/p>\n

alien:~$ echo $[ 4 * 2 ]
\n8
\nalien:~$<\/p>\n

or another example:<\/p>\n

alien:~$ echo $[ 10 + 5 ]
\n15
\nalien:~$<\/p>\n

Easy ? …. I think it is =)<\/p>\n

The internal calculator can also be used like this:<\/p>\n

alien:~$ echo $(( 10 + 5 ))
\n15
\nalien:~$<\/p>\n

The second way of using the internal shell calculator is here just
\nso you dont get confused if you see it used that way sometime.<\/p>\n

——————————————————————————-<\/p>\n

Now I’d like to show the *string comparing* with “if” statements,
\nwhich can be a little hard at first contact, but as soon as you get
\nfamiliar with it, it wont be any problems.
\nSo here’s an example.<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

echo -n “enter a name: ”
\nread var1
\necho -n “enter another name: ”
\nread var2<\/p>\n

if [ “$var1” = “$var2” ]; then
\necho “The names are the same”
\nelse
\necho “The names were not the same”
\nfi<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Note: “fi” is the ending of if, just like a “}” is the ending of a “{“,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 exit 0 terminates the script correctly and returns you to the prompt.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Another note is that instead of ‘=’ you can use ‘-eq’ to test if
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2 expressions are equal, or ‘-eg’ to check if 2 integers are equal, etc.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 It should also be said that a variable say ‘$var’ can be written
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 as this: ${var}, just so you know if you see it done that way
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 in some scripts, but here we will use the $var way.<\/p>\n

——————————————————————————-<\/p>\n

This example if executed looks like this:<\/p>\n

(Matching names)<\/p>\n

alien:~$ .\/script1.sh
\nenter a name: smurf
\nenter another name: smurf
\nThe names are the same
\nalien:~$<\/p>\n

(Non-matching names)<\/p>\n

alien:~$ .\/script1.sh
\nenter a name: smurf
\nenter another name: guru
\nThe names were not the same
\nalien:~$<\/p>\n

You can compare any 2 strings with this, as this *mid script example*:<\/p>\n

…
\nif [ “$user” = “gnu” ]; then
\necho “Hello user gnu !”
\nelse
\necho “I don’t know you.”
\nfi
\n…<\/p>\n

This compares a variable with a static string which you can set to anything.
\nYou can also do this the other way around.<\/p>\n

…
\nif [ “$user” != “gnu” ]; then
\necho “I don’t know you.”
\nelse
\necho “Hello user gnu !”
\nfi
\n…<\/p>\n

The ‘!=’ means NOT-IS, in clear text if the 2 strings are not a match.
\nAs the above example in straight English:<\/p>\n

…
\nif the variable don’t match the word gnu, then
\nsay “I don’t know you.”
\nin other cases
\nsay “Hello user gnu !”
\n…<\/p>\n

If you think that a variable may not contain anything and you wanna avoid
\nit showing you errors you can add an x as the first character to both
\nthe statements to test with if, like this to compare $one with -x:<\/p>\n

…
\nif [ “x$one” = “x-x” ]; then
\necho “$one is -x”
\nelse
\necho “$one is not -x”
\nfi
\n…<\/p>\n

In plain english:<\/p>\n

…
\nif (contents of $one) equals -x (supress error messages if any), then
\nsay (contents of $one) is -x
\nin other cases
\nsay (contents of $one) is not -x
\n…<\/p>\n

This previous way is actually quite old, and only a precaution, say this:<\/p>\n

…
\necho -n “enter a number: ”
\nread foo
\nif [ $foo = 2 ]; then
\necho ok foo
\nfi
\n…<\/p>\n

Now, if you with this example dont enter any number there will be nothing
\nthere for if to compare with, not even a blank “”, since we’re not
\nusing quotes, but as this:<\/p>\n

…
\necho -n “enter a number: ”
\nread foo
\nif [ x$foo = x2 ]; then
\necho ok foo
\nfi
\n…<\/p>\n

There will always be something, because if $foo is nothing there is
\nstill x.
\nJust read acouple of times and you’ll get it.<\/p>\n

You can also test if a variable contains anyting at all like this:<\/p>\n

…
\necho -n “enter a number: ”
\nread foo
\n[ -n $foo ] &&
\necho ok foo
\n…<\/p>\n

This uses the same options as the test command, so “-z” will return true
\nif the variable is empty, “-z” will return true if the variable is not
\nempty etc, it’s ok if you dont understand this right now ….
\nI’ve added this for the second time readers.<\/p>\n

You can also test if a command turns out as true, like this:<\/p>\n

…
\nif echo “foo” >\/dev\/null; then
\necho “foo”
\nelse
\necho “bar”
\nfi
\n…<\/p>\n

Here if will check if foo echos to \/dev\/null, and if so, then it will
\nprint out “foo” and if foo didnt echo to \/dev\/null, it’ll print out
\nthe word “bar”<\/p>\n

Anoter and perhaps *cleaner* way of doing the same is this:<\/p>\n

…
\nif (echo “foo” >\/dev\/null); then
\necho “foo”
\nelse
\necho “bar”
\nfi
\n…<\/p>\n

It’s the exact same thing but with parenthases around the command,
\nit looks much cleaner … and so the code is easyer to follow.<\/p>\n

You can also make if think ‘if this is a match or that is a match’, like
\nif the variable is one of two options do one thing else do another.
\nLike this:<\/p>\n

…
\nif [ “$user” = “gnu” -o “$user” = “ung” ]; then
\necho “Hello $user !”
\nelse
\necho “I never heard of $user…”
\nfi
\n…<\/p>\n

The ‘-o’ means OR in an if statement, so here is the example in plain english:<\/p>\n

…
\nif the variable matches the word gnu or matches the word ung, then
\nsay Hello word ! (the word is the variable, now gnu or ung)
\nin other cases
\nsay “I never heard of word… (the word is whatever the variable is set to)
\n…<\/p>\n

——————————————————————————-<\/p>\n

Note: The quotes are needed in an if statement in case the strings or
\n\u00a0\u00a0\u00a0\u00a0\u00a0 variables it’s suppse to compare is empty, since
\n\u00a0\u00a0\u00a0\u00a0\u00a0 if [ foo =\u00a0 ]; then
\n\u00a0\u00a0\u00a0\u00a0\u00a0 would produse a syntax error, but
\n\u00a0\u00a0\u00a0\u00a0\u00a0 if [ “foo” = “” ]; then
\n\u00a0\u00a0\u00a0\u00a0\u00a0 would not.<\/p>\n

——————————————————————————-<\/p>\n

The ‘-o’ can also be made with ‘] || [‘, so that:
\nif [ “$user” = “gnu” -o “$user” = “ung” ]; then
\ncan also be expressed as this:
\nif [ “$user” = “gnu” ] || [ “$user” = “ung” ]; then
\nYou dont really need to remember that, but for the knowlidge I desided
\nto make a note out of that anyway, mostly for the more experianced readers
\nof this tutuorial, and for the readers that have read it several times.<\/p>\n

——————————————————————————-<\/p>\n

You can also set static text in a variable, which is really easy:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

anyvar=”hello world”<\/p>\n

echo “$anyvar”<\/p>\n

exit 0
\n——————————————————————————-<\/p>\n

Which executed would look like this:<\/p>\n

alien:~$ .\/myscript
\nhello world
\nalien:~$<\/p>\n

Easy enough ? =)<\/p>\n

——————————————————————————-<\/p>\n

Now let’s move on to “for” and common for-loops.
\nI am actually only going to show one sort of for-loop example, of the reason that
\nat this stage no more is needed, and would only confuse.
\nas a note, for loops-can be uses (as soon shown) to import strings
\nfrom a file to be used as variables in the script.<\/p>\n

Now, here’s the example:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

for VAR in `cat list.txt`; do
\necho “$VAR was found in list.txt”
\ndone<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Note: “done” terminates the loop when finished.
\n\u00a0\u00a0\u00a0\u00a0\u00a0 “in” and “do” are like bash *grammar*, I’ll explain that later.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0 The `cat list.txt` part, the `s around the command will make sure
\n\u00a0\u00a0\u00a0\u00a0\u00a0 the script\/line executes that part as a command, another way of
\n\u00a0\u00a0\u00a0\u00a0\u00a0 doing this is to: $(cat list.txt)
\n\u00a0\u00a0\u00a0\u00a0\u00a0 which has the same effect.
\n\u00a0\u00a0\u00a0\u00a0\u00a0 That’s just a note so you wont get confused if you see it used
\n\u00a0\u00a0\u00a0\u00a0\u00a0 that way some time.<\/p>\n

——————————————————————————-<\/p>\n

The previous script example is dependent on that there is a file called
\n“list.txt”, so let’s make such, and fill it with something like this:<\/p>\n

list.txt<\/p>\n

123
\n234
\n345
\n456
\n567
\n678
\n789
\n890<\/p>\n

——————————————————————————-<\/p>\n

Then the executed script would look like this:<\/p>\n

alien:~$ .\/script2.sh
\n123 was found in list.txt
\n234 was found in list.txt
\n345 was found in list.txt
\n456 was found in list.txt
\n567 was found in list.txt
\n678 was found in list.txt
\n789 was found in list.txt
\n890 was found in list.txt
\nalien:~$<\/p>\n

——————————————————————————-<\/p>\n

Note: A space in a file read by a for-loop is taken the same way as a new line.<\/p>\n

——————————————————————————-<\/p>\n

Here is another example, with a for-loop with an if statement:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

for VAR3 in `cat list.txt`; do
\nif [ “$VAR3” = “789” ]; then
\necho
\necho “Match was found ($VAR)”
\necho
\nfi
\ndone<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

And executed that looks like this:<\/p>\n

alien:~$ .\/script3.sh<\/p>\n

Match was found (789)<\/p>\n

alien:~$<\/p>\n

If you have read this in a calm fashion it should be quite clear to you
\nso far, but before I move on to real practice examples I will explain
\nthe while-loop, and some, more which can be used as to count and more,
\nfor various purposes, as you will see.
\nYou don’t have to *understand* all of how this works, but you should
\nat least learn it.<\/p>\n

So here we go on an example with “while”:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

count=”0″
\nmax=”10″<\/p>\n

while [ $count != $max ]; do count=`expr $count + 1`
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “We are now at number: $count”
\ndone<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Note: expr is a calculator command, you can read more about it later in
\n\u00a0\u00a0\u00a0\u00a0\u00a0 this tutorial.<\/p>\n

——————————————————————————-<\/p>\n

This in plain English reads the following:<\/p>\n

make variable “count” hold the number 0
\nmake variable “max” hold the number 10<\/p>\n

while 0 is not 10, do add 1 to 0 (each loop until it is 10)
\nsay “We are now at number: $count” (each time 1 is added as long as we are
\nin the loop)
\nend the loop
\nreturn to the prompt command line.<\/p>\n

——————————————————————————-<\/p>\n

Which executed looks like, (you guessed it), this:<\/p>\n

alien:~$ .\/count.sh
\nWe are now at number: 1
\nWe are now at number: 2
\nWe are now at number: 3
\nWe are now at number: 4
\nWe are now at number: 5
\nWe are now at number: 6
\nWe are now at number: 7
\nWe are now at number: 8
\nWe are now at number: 9
\nWe are now at number: 10
\nalien:~$<\/p>\n

——————————————————————————-<\/p>\n

Here is another example of a while loop.<\/p>\n

#!\/bin\/bash<\/p>\n

agreement=
\nwhile [ x$agreement = x ]; do
\n\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0 echo -n “Do you agree with this ? [yes or no]: ”
\n\u00a0\u00a0\u00a0 read yesnoanswer
\n\u00a0\u00a0\u00a0 case $yesnoanswer in
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 y* | Y*)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 agreement=1
\n\u00a0 ;;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 n* | n*)
\n\u00a0\u00a0\u00a0\u00a0\u00a0 echo “If you don’t agree, you can’t install this sofware”;
\n\u00a0\u00a0\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0\u00a0\u00a0 exit 1
\n\u00a0 ;;
\n\u00a0\u00a0\u00a0 esac
\ndone<\/p>\n

echo “agreed”
\necho
\n——————————————————————————-<\/p>\n

This in plain English reads the following:<\/p>\n

Make an unknown variable named agreement
\nwhile the unknown variable is unknown and doesnt match the case,
\nsay “Do you agree with this ? [yes or no]: ”
\nread the the answer into the “yesnoanswer” variable.
\nmake a case and check the “yesnoanswer” variable for any words beginning
\nwith y or Y, and if so, skip the rest and go on with the script
\nand say “agreed”.
\nif it doesnt begin with y or Y, check if it starts with n or N.
\nIf it does start with a n or N, then say:
\n“If you don’t agree, you can’t install this sofware”
\nand quit the script.<\/p>\n

——————————————————————————-<\/p>\n

Which executed looks like this:<\/p>\n

alien:~$ .\/agree.sh<\/p>\n

Do you agree with this ? [yes or no]: something<\/p>\n

Do you agree with this ? [yes or no]: yes
\nagreed<\/p>\n

Again executed, but with ‘no’ as answer:<\/p>\n

alien:~$ .\/agree.sh<\/p>\n

Do you agree with this ? [yes or no]: nothing
\nIf you don’t agree, you can’t install this sofware<\/p>\n

alien:~$<\/p>\n

——————————————————————————-<\/p>\n

Note that “nothing” begins with ‘n’ and therfor matches what the script is
\nlooking for, y or Y, and n or N.<\/p>\n

Also see later in the tutorial about `case` statements.<\/p>\n

——————————————————————————-<\/p>\n

Now I’m going to explain shortly about functions in bash.<\/p>\n

A function is like a script within the script, or you could say that
\nyou make your own little command that can be used in a script.
\nIt’s not as hard as it sounds though.<\/p>\n

So here we go on a example:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

function myfunk {
\necho
\necho “hello”
\necho “this is my function”
\necho “which I will display twice”
\n}<\/p>\n

myfunk
\nmyfunk<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Which executed looks like this:<\/p>\n

alien:~$ .\/funk.sh<\/p>\n

hello
\nthis is my function
\nwhich I will display twice<\/p>\n

hello
\nthis is my function
\nwhich I will display twice
\nalien:~$<\/p>\n

——————————————————————————-<\/p>\n

Another example of functions can look like this:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

myvar=”$1″
\nvar2=”$2″<\/p>\n

if [ “$myvar” = “” ]; then
\necho “Usage: $0 <integer> <integer>”
\nexit 0
\nfi<\/p>\n

function myfunk {
\nexpr $1 + $2
\n}<\/p>\n

myfunk $myvar $var2<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Which executed looks like this:<\/p>\n

Without any arguments:<\/p>\n

alien:~$ .\/funk.sh
\nUsage: .\/funk.sh <integer> <integer><\/p>\n

With arguments:<\/p>\n

alien:~$ .\/funk.sh 12 3
\n15
\nalien:~$<\/p>\n

——————————————————————————<\/p>\n

Note: the $1 and $2 in the function is infact the first and second argument
\n\u00a0\u00a0\u00a0\u00a0\u00a0 supplied after the function name when it’s called for within the script,
\n\u00a0\u00a0\u00a0\u00a0\u00a0 so you could say that a function is like a separate scrip in
\n\u00a0\u00a0\u00a0\u00a0\u00a0 the main script.<\/p>\n

——————————————————————————<\/p>\n

Yet another example of a function is this:<\/p>\n

——————————————————————————<\/p>\n

#!\/bin\/bash<\/p>\n

myvar=”$1″<\/p>\n

if [ “$myvar” = “” ]; then
\necho “Usage: $0 <number>”
\nexit 0
\nfi<\/p>\n

function calcfunc { expr 12 + $1 ; }<\/p>\n

myvar2=`calcfunc 5`<\/p>\n

echo “welcome”
\necho “Now we will calculate 12 + 5 * $myvar”<\/p>\n

echo “the answer is `expr $myvar2 ‘*’ $myvar`”<\/p>\n

——————————————————————————-<\/p>\n

Which executed looks like this:<\/p>\n

Without any arguments:<\/p>\n

alien:~$ .\/funk.sh
\nUsage: .\/funk.sh <number>
\nalien:~$<\/p>\n

And with arguments:<\/p>\n

alien:~$ .\/funk.sh 23
\nwelcome
\nNow we will calculate 12 + 5 * 23
\nthe answer is 391
\nalien:~$<\/p>\n

——————————————————————————<\/p>\n

And for the sake of knowlidge it should also be said that a function can be
\ndeclared in the following ways aswell:<\/p>\n

——————————————————————————<\/p>\n

#!\/bin\/bash<\/p>\n

function foo() {
\necho “hello world”
\n}<\/p>\n

foo<\/p>\n

——————————————————————————<\/p>\n

#!\/bin\/bash<\/p>\n

foo () {
\necho “hello world”
\n}<\/p>\n

foo<\/p>\n

——————————————————————————<\/p>\n

Note that the paranteses after the funtion name are the new thing here.
\nIt’s used exactly the same way as without the paranteses, I just
\nadded that here so that you wont get confused if you see it made that
\nway sometime.<\/p>\n

——————————————————————————<\/p>\n

So if you make a function, to call for it (to make use of it), just use the
\nthe functions name just as if it had been a command.<\/p>\n

If there is anything that’s uncertain at this point, go back and read it again,
\nuntil you understand it, or at least get the basic idea. =)<\/p>\n

===============================================================================
\n3 – Other techniques.
\n===============================================================================<\/p>\n

Now let’s move on to a little bit more advanced shell scripting.
\nActually it’s not that advanced, just more hard to keep in order, but let us
\nleave that to the head of the beholder….. errr
\nAnyway, let’s not make this harder then it is, so here we go, with a script
\nexample:<\/p>\n

——————————————————————————-
\n#!\/bin\/bash<\/p>\n

> file1.c<\/p>\n

cat >> file1.c << EOF
\n#include <stdio.h>
\nint main ( void )
\n{
\n\u00a0 printf(“Hello world\\n”);
\n\u00a0 return 0;
\n}
\nEOF<\/p>\n

cc file1.c -o file1 || gcc -o file1 file1.c
\n.\/file1<\/p>\n

rm -f file1.c file1<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

And here as follows, is an semi-english translation of the script:<\/p>\n

echo nothing to file1.c to create it.<\/p>\n

cat to file1.c what comes here after in between the “EOF”‘s
\n\/\/ — a short hello world program in C code — \/\/<\/p>\n

try if there is a ‘cc’, if not then use ‘gcc’
\nExecute the newly compiled file<\/p>\n

remove file1.c and file1<\/p>\n

exit the script.<\/p>\n

——————————————————————————-<\/p>\n

This can be very useful, since bash do have it’s limitations, so if you
\never need something more powerful or just something else, you can always
\ndo like the script told.<\/p>\n

Another little trick with the same thing in a script is:<\/p>\n

more << EOF
\nHere you can type whatever,
\nlike an agreement text or something.
\nEOF<\/p>\n

Play around with it.<\/p>\n

——————————————————————————-<\/p>\n

Here let’s have a look at the “case” command, case is like “if” ended
\nwith it self backwards.
\nSo that what starts with “case” ends with “esac”, here’s an example of “case”:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

case “$1” in
\n\u00a0\u00a0\u00a0 foo)
\n\u00a0\u00a0\u00a0 echo “foo was written”
\n\u00a0\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 bar)
\n\u00a0\u00a0\u00a0 echo “bar was written”
\n\u00a0\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 something-else)
\n\u00a0\u00a0\u00a0 echo “something-else was written”
\n\u00a0\u00a0\u00a0 ;;
\nesac<\/p>\n

——————————————————————————-<\/p>\n

This is the same as saying:<\/p>\n

….
\nif [ “$1” = “foo” ];then
\necho “foo written”
\nfi
\nif [ “$1” = “bar” ];then
\necho “bar was written”
\nfi<\/p>\n

etc.
\n….<\/p>\n

so case is far shorter if you have alot of arguments.<\/p>\n

Here’s a better example:<\/p>\n

——————————————————————————-
\n#!\/bin\/bash<\/p>\n

case “$1” in
\n\u00a0\u00a0\u00a0 –help)
\n\u00a0\u00a0\u00a0 echo “Usage: $0 [–help] [–port <port>] <host> [–time]”
\n\u00a0\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 –port)
\n\u00a0\u00a0\u00a0 telnet $3 $2
\n\u00a0\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 –time)
\n\u00a0\u00a0\u00a0 date
\n\u00a0\u00a0\u00a0 ;;
\nesac<\/p>\n

——————————————————————————-<\/p>\n

This is not very hard to learn,
\ncase the first argument vector ($1) in
\nfirt-possible-match)
\nif it matches do ……..
\nclose the ) with ;;
\netc. down to “esac”<\/p>\n

Really not much more to say about the case command at this point.<\/p>\n

——————————————————————————-<\/p>\n

Now let’s have a REALLY quick look at the command `sed`, which is used
\nto format text. say now that you have a file called “tmp” that
\ncontains the following:<\/p>\n

http:\/\/www.metacrawler.com<\/a>
\nhttp:\/\/www.yahoo.com<\/a>
\nhttp:\/\/www.webcrawler.com<\/a><\/p>\n

and you want to change all the “www”‘s to “ftp”, then you do like this:<\/p>\n

sed ‘s\/www\/ftp\/g’ tmp<\/p>\n

and if you want to store the changes to a file you can do:<\/p>\n

sed ‘s\/www\/ftp\/g’ tmp > tmp2<\/p>\n

This is not sed’s only use, but for sure it’s what it’s most used for.<\/p>\n

Here’s just one other really simple thing sed could be used as:<\/p>\n

sed -n 3 p \/etc\/passwd<\/p>\n

This will print out the 3’d line of the \/etc\/passwd file.<\/p>\n

——————————————————————————-<\/p>\n

Now let’s take up a really interesting command `dialog`, that is a command
\nwith which you can create ncurses dialog boxes.
\nNcurses dialog boxes are what one would call ‘console graphics’ or
\n‘ascii color graphics’, if you ever seen a blue background and a gray box
\nasking questions, with an <OK> and <Cancel> button, while running
\nsomething in a console you have seen an ncurses dialog box.<\/p>\n

Now here is a small script example of a dialog box:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

dialog –backtitle “My first dialog” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –title “Main menu” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –menu “Make your choice” 13 60 6 \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 “First option” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2 “Second option” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3 “Exit” 2> .tempfile
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output=`cat .tempfile`
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 rm -f .tempfile<\/p>\n

if [ “$output” = “1” ]; then
\ndialog –msgbox “First option was entered” 5 40
\nfi<\/p>\n

if [ “$output” = “2” ]; then
\ndialog –msgbox “Second option was entered” 5 40
\nfi<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Here is another very small example with dialog boxes:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

dialog –yesno “Do you agree, jada jada” 10 50 && \\
\ndialog –yesno “ok you agreed” 10 50 || \\
\ndialog –yesno “ok fine, leav then …” 10 50<\/p>\n

——————————————————————————-<\/p>\n

If the first one (Do you agree, jada jada) returns ‘true’ (yes)
\nthen it walks on to the next (ok you agreed),
\nand if any of those first two returns ‘false’ (no) it will display
\nthe last (ok fine, leav then …).<\/p>\n

——————————————————————————-<\/p>\n

Notes: The back slashes “\\” are used to say “no new line” as in what comes
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 on the next line will be treated as if it were on the same line as
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the last line, the “\\” really means that the next character’s
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (in this case the new lines) special meaning is overlocked.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Just in case you didnt understand, the numbers after, like 10 50:
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 dialog –yesno “ok fine, leav then …” 10 50
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is the geometry of the window.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 First number is height and the second width.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Another note being that the command `Xdialog` works the same as
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 dialog, but I wont take that up here because it doesn’t come as default
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 with any other Linux distribution then Mandrake, as far as I know.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A final note is that the `dialog` command is getting to be out dated
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 but is still the most used, the newer version of it is named `whiptail`
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 and works the same as `dialog`, but looks slightly different.<\/p>\n

——————————————————————————-<\/p>\n

Now we have covered most of it, so let’s take up some small tricks, that bash
\nallows you to do, here follows what it does, and then the code example:<\/p>\n

Here we wanna check if you have a directory called “\/usr\/local\/bin”:<\/p>\n

if [ -d \/usr\/local\/bin ]; then
\ncp file \/usr\/local\/bin\/
\nelse
\necho “NO !!”
\nfi<\/p>\n

Another way of doing the same thing is this:<\/p>\n

test -d \/usr\/local\/bin && cp file \/usr\/local\/bin\/ || echo “NO !!”<\/p>\n

Or:<\/p>\n

ls \/usr\/local\/bin\/ && cp file \/usr\/local\/bin\/ || echo “NO !!”<\/p>\n

The last way is a bit messy, but alot smaller then the first one,
\nbut here’s yet another way that’s small and less messy:<\/p>\n

ls \/usr\/local\/bin\/ 1>\/dev\/null 2>&1 && cp file \/usr\/local\/bin\/ || echo “NO !!”<\/p>\n

That might look really weird at first sight, but it’s easy if you break it
\ndown and look at it:<\/p>\n

ls \/usr\/local\/bin\/ <<==== lists \/usr\/local\/bin\/
\n1>\/dev\/null\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <<==== sends the contents of the listing to ‘the black hole’
\n2>&1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <<==== sends any errors the same way… to ‘the black hole’
\n\u00a0\u00a0\u00a0\u00a0 (same thing as to say 2>\/dev\/null)
\n&&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <<==== if the first command worked, we will go on here.
\ncp file \/usr\/local\/bin\/\u00a0\u00a0 <<==== copy file to \/usr\/local\/bin\/
\n||\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <<==== if the\u00a0 first command didn’t work…
\n\u00a0\u00a0\u00a0\u00a0 we go on here instead.
\necho “NO !!”\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <<==== what it says … say NO !!<\/p>\n

as this:
\nIf `ls` can list \/usr\/local\/bin\/ next command can be executed, OR if not
\nit will echo “NO !!”, and all listings\/errors are being sent to \/dev\/null
\nthe ‘black hole’ of a UNIX\/Linux.<\/p>\n

——————————————————————————-<\/p>\n

To prevent that a script is being executed more the once at the same time
\nfor some reason you may wanna let the script make a ‘lock’ file.
\nThis is very easy to do:<\/p>\n

#!\/bin\/bash
\nls script.lock 1>\/dev\/null 2>&1 && exit 0 && echo “lockfile detected”
\n> script.lock
\necho “Here is where the script should be”
\nrm -f script.lock
\nexit 0<\/p>\n

Here we first check if there is a lockfile, and if there is we terminate
\nthe script and say that a lockfile was detected.
\nIf there is no lockfile, we create one and start to execute the rest of the
\nscript.
\nAt the end of the script we remove the lockfile, so that the script can
\nbe executed again.
\nAll this is just to prevent the same script to be run twice at the same time,
\nwhich can be a good thing if your script does something that cant be done
\ntwice at the same time, as mounting a hard drive\/cd-rom, using sound or
\nanything like that.<\/p>\n

Another neat little trick is if you from within a script are going to
\ncreate temporary files that you want unique (to not overwrite some other
\nfiles anywhere, wherever the script may get executed) you can do like this:<\/p>\n

#!\/bin\/bash
\necho “ls” >.tmp.$$
\necho “-la” >.tmp2.$$
\none=`cat .tmp.$$`
\ntwo=`cat .tmp2.$$`
\n$one $two
\nrm -f .tmp.$$ .tmp2.$$<\/p>\n

This will make a file called .tmp.<pid of script> containing the word “ls”,
\nthen it will make a file called .tmp2.<pid of script> containing “-la”.
\nAfter that it make 2 variables, each one when being called will `cat` one
\nof the .tmp.* files each.
\nAt the end we have “$one $two” that will work the same as if we had printed:<\/p>\n

ls -la<\/p>\n

And last we remove the temporary files.<\/p>\n

This is useful if your doing a script that requires you to move around alot
\nof text from one file to another and back, as this example:<\/p>\n

#!\/bin\/bash<\/p>\n

sed ‘s\/www\/ftp\/g’ tmp > .tmp.$$
\nsed ‘s\/com\/org\/g’ .tmp.$$ > .tmp2.$$
\nsed ‘s\/ \/_\/g’ .tmp2.$$ > .tmp3.$$
\nmv -f .tmp3.$$ tmp
\nrm -f .tmp.$$ .tmp2.$$ .tmp3.$$<\/p>\n

exit 0<\/p>\n

Here we change all www’s in a file (tmp) to ftp, then we change all com’s
\nto org, and then all spaces to underscores.
\nAfter that we move the fully changed file so it overwrites the original file.
\nThen removing the temporary files and exit the script.<\/p>\n

If you have a good look at it, it’s really easy.<\/p>\n

Another nice trick is as I showed in the example prior to the last one:<\/p>\n

…
\none=`cat .tmp.$$`
\ntwo=`cat .tmp2.$$`
\n…<\/p>\n

That a variable can hold a command can prove to be useful, like this:<\/p>\n

#!\/bin\/bash
\ntime=`date +%H:%M:%S`<\/p>\n

echo “$time” >> log
\necho “some input to the log” >> log
\nsleep 60
\necho “$time” >> log
\necho “some input to the log a minute later” >> log<\/p>\n

exit 0<\/p>\n

But, it can hold more then just a command, it can actually *hold* the contents
\nof a whole file.
\nSay now that you made a script and have a pretty large readme file, and want
\nto display that as a ‘man page’ to the script if the argument `–help`
\nis used to execute the script, then you can do like this:<\/p>\n

#!\/bin\/bash
\none=”$1″
\nhelp=`cat README`<\/p>\n

if [ “$one” = “–help” ]; then
\n$help | more
\n…<\/p>\n

Ofcorce it would be easier to say:<\/p>\n

#!\/bin\/bash
\nif [ “$?” = “–help” ]; then
\nmore README
\nfi<\/p>\n

But these examples are just here for illustration so you get the point
\nof usage for commands and so.<\/p>\n

Another trick is, if you wanna hide script\/program you can rename it to:
\n-bash, that way it will look as a normal bash running in the `ps`
\n(process list), you rename it by doing:<\/p>\n

mv script .\/-bash<\/p>\n

Then execute it like normal .\/-bash<\/p>\n

Yet another trick, is if you’re doing a script where you want each line
\nof a file as a variable, unlike for that takes each word as a variable.
\nThis can be done like this:<\/p>\n

#!\/bin\/bash
\nfile=”$1″
\nmin=”0″
\nmax=`cat $file | wc -l`<\/p>\n

if [ “$1” = “” ]; then
\necho “Usage: $0 <file>”
\nexit -1
\nfi<\/p>\n

while [ “$min” != “$max” ]; do min=`expr $min + 1`
\ncurline=`head -$min $file | tail -1`
\necho $curline
\ntest $min -eq $max && exit 0
\ndone<\/p>\n

The `test` is there to make sure that it will end when $min and $max are the
\nsame.
\nNow this can be done with `for` if you change IFS (described later), but that
\nis not recomended, especially if you export IFS since that would change the
\nenviorment and hence screw with the system scripts if they were to be runned
\nbefore changing IFS back to normal, but enough about that now, just keep
\nit somewhere far back in your head, dont change IFS unless you know what
\nyou’re doing.<\/p>\n

If you dont understand this little script at this point, dont worry, you
\nwill understand it the second time you read this tutorial =)<\/p>\n

——————————————————————————-<\/p>\n

Now let’s take a quick look at arrays in shell scripting.
\nFirst off, an array is what it says, it’s an array of something,
\nnow, to declare a variable that can hold an array we create it with the
\ncommand `declare`, let’s make a short example:<\/p>\n

alien:~$ declare -a foo=(1 2 3 4 5)
\nalien:~$ echo ${foo[0]}
\n1
\nalien:~$ echo ${foo[1]}
\n2
\nalien:~$ foo[1]=bar
\nalien:~$ echo ${foo[1]}
\nbar
\nalien:~$<\/p>\n

First of all, to understand the declare command better do `help declare`
\nat a console and it’ll desplay this:<\/p>\n

declare: declare [-afFrxi] [-p] name[=value] …
\n\u00a0\u00a0\u00a0 Declare variables and\/or give them attributes.\u00a0 If no NAMEs are
\n\u00a0\u00a0\u00a0 given, then display the values of variables instead.\u00a0 The -p option
\n\u00a0\u00a0\u00a0 will display the attributes and values of each NAME.<\/p>\n

\u00a0\u00a0\u00a0 The flags are:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0 -a\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to make NAMEs arrays (if supported)
\n\u00a0\u00a0\u00a0\u00a0\u00a0 -f\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to select from among function names only
\n\u00a0\u00a0\u00a0\u00a0\u00a0 -F\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to display function names without definitions
\n\u00a0\u00a0\u00a0\u00a0\u00a0 -r\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to make NAMEs readonly
\n\u00a0\u00a0\u00a0\u00a0\u00a0 -x\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to make NAMEs export
\n\u00a0\u00a0\u00a0\u00a0\u00a0 -i\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to make NAMEs have the `integer’ attribute set<\/p>\n

\u00a0\u00a0\u00a0 Variables with the integer attribute have arithmetic evaluation (see
\n\u00a0\u00a0\u00a0 `let’) done when the variable is assigned to.<\/p>\n

\u00a0\u00a0\u00a0 When displaying values of variables, -f displays a function’s name
\n\u00a0\u00a0\u00a0 and definition.\u00a0 The -F option restricts the display to function
\n\u00a0\u00a0\u00a0 name only.<\/p>\n

\u00a0\u00a0\u00a0 Using `+’ instead of `-‘ turns off the given attribute instead.\u00a0 When
\n\u00a0\u00a0\u00a0 used in a function, makes NAMEs local, as with the `local’ command.<\/p>\n

So here we see that the -a switch to declare makes the variable an array.
\nSo after getting that `declare -a` we declare the variable as an array,
\nwith the array within paranteses.<\/p>\n

And then to make use of it, we use the way to write a variable like this:
\n${ variable name here }
\nand the number inside the []’s is the number that points to which part of
\nthe array it should use, begining from 0 which is the first.<\/p>\n

Let’s make another short example:
\ndeclare -a foo=(this is another example)
\necho “The array (${foo[*]}) has (${foo[0]}) as first, and (${foo[3]}) as last.”<\/p>\n

The output of this would be:
\nThe array (this is another example) has (this) as first, and (example) as last.<\/p>\n

Now, this isn’t something you’ll use in every day scripting, but it’s still
\nsomething you should know the existance of, just in case you see it or need
\nit at some point.<\/p>\n

——————————————————————————-<\/p>\n

Now here’s a less common way of using bash, CGI scripts.
\nMost people dont assosiate shell scripting with cgi, but it works
\njust as well as any other language, so here I’d like to to show
\nyou how to make CGI scripts in bash.<\/p>\n

——————————————————————————-<\/p>\n

Here is the first example which is a simple cgi counter in bash.
\nA note is that all CGI scripts should be in the servers cgi-bin directory
\nor any subdirectory there off, unless the server is configured to see
\nany other directorys as cgi directorys.<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

test -f date.txt || echo `date “+%B %d %Y”` > date.txt
\ntest -f counter.txt || echo ‘0’ > counter.txt
\ncurrent=`cat counter.txt`
\ndate=`cat date.txt`
\nvisitor=`expr $current + 1`<\/p>\n

echo “$visitor” > counter.txt
\necho ‘Content-type: text\/html’
\necho ”
\necho ‘<br>Vitor:’
\necho ‘<br>’$visitor'<br>Since’
\necho ‘<br>’$date'<\/br>’<\/p>\n

——————————————————————————-<\/p>\n

Let’s take this one line by line here:<\/p>\n

First the shell ….
\n#!\/bin\/bash<\/p>\n

Then we test if there is a file called date.txt, if not then we echo the
\ncurrent date to it and hence creating it.
\ntest -f date.txt || echo `date “+%B %d %Y”` > date.txt<\/p>\n

Then we test if there is a file called counter.txt and if not we echo a 0
\nto it and so create that one too.
\ntest -f counter.txt || echo ‘0’ > counter.txt<\/p>\n

Now we declare the variables, current is the contents of counter.txt.
\ncurrent=`cat counter.txt`<\/p>\n

The date variable is the contents of date.txt.
\ndate=`cat date.txt`<\/p>\n

And visitor is the sum of the contents of counter.txt + 1.
\nvisitor=`expr $current + 1`<\/p>\n

And then we echo the new increased number to counter.txt.
\necho “$visitor” > counter.txt<\/p>\n

And here comes the HTML part. the first to line is the ‘cgi header’
\nthose should ALWAYS be there:
\necho ‘Content-type: text\/html’
\necho ”<\/p>\n

Then we move on to the *real* html:
\necho ‘<br>Vitor:’
\necho ‘<br>’$visitor'<br>Since’
\necho ‘<br>’$date'<\/br>’<\/p>\n

The <br> is a linebreak in html
\nThe bash variables have to be *ouside* the ‘s else they will simply show
\nup as $visitor or $date litterly, that’s why it’s made like this:
\necho ‘text’ $variable ‘some more text’
\nSo that the text is enclosed with ‘s, but the variables are between or rather
\noutside of them.
\nAnyway, this cgi will create a section that looks like this on a webpage:<\/p>\n

—————-
\n\u00a0\u00a0 Vitor:
\n\u00a0\u00a0\u00a0\u00a0 1
\n\u00a0\u00a0 Since
\nMay 29 2001
\n—————-<\/p>\n

To add that to a html code you add this tag to your html\/shtml page:
\n<!–#exec cgi=”<path to counter>” –><\/p>\n

With the path to the counter it could look like this:<\/p>\n

<!–#exec cgi=”\/cgi-bin\/counter\/counter.cgi” –><\/p>\n

Not so hard is it ?<\/p>\n

——————————————————————————-<\/p>\n

Here is another example of a CGI script in bash (actually the second CGI
\nscript I ever made).<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

method=`echo $QUERY_STRING | awk -F’=’ ‘{print $1}’`
\nhost=`echo $QUERY_STRING | awk -F’=’ ‘{print $2}’`<\/p>\n

if [ “$method” = “nslookup” ]; then
\necho ‘Content-type: text\/html’
\necho ”
\necho ‘<html>’
\necho ‘<body bgcolor=”white”>’
\necho ‘<center>’
\necho ‘<br>nslookup ‘$host’ (This might take a second)<br>’
\necho ‘<hr width=”100%”>’
\necho ‘<\/center>’
\necho ‘<pre>’
\nnslookup $host
\necho ‘<\/pre>’
\necho ‘<center>’
\necho ‘<hr width=”100%”>’
\necho ‘<br>nslookup compleat’
\necho ‘<\/center>’
\necho ‘<\/body>’
\necho ‘<\/html>’
\nfi<\/p>\n

if [ “$method” = “ping” ]; then
\necho ‘Content-type: text\/html’
\necho ”
\necho ‘<html>’
\necho ‘<body bgcolor=”white”>’
\necho ‘<center>’
\necho ‘<br>ping ‘$host’ (This might take a second)<br>’
\necho ‘<hr width=”100%”>’
\necho ‘<\/center>’
\necho ‘<pre>’
\nping -c 5 $host
\necho ‘<\/pre>’
\necho ‘<center>’
\necho ‘<hr width=”100%”>’
\necho ‘<br>ping compleat’
\necho ‘<\/center>’
\necho ‘<\/body>’
\necho ‘<\/html>’
\nfi<\/p>\n

if [ “$method” = “scan” ]; then
\necho ‘Content-type: text\/html’
\necho ”
\necho ‘<html>’
\necho ‘<body bgcolor=”white”>’
\necho ‘<center>’
\necho ‘<br>Scanning host ‘$host’ (This might take a minute)<br>’
\necho ‘<hr width=”100%”>’
\necho ‘<\/center>’
\necho ‘<pre>’
\nnmap $host
\necho ‘<\/pre>’
\necho ‘<center>’
\necho ‘<hr width=”100%”>’
\necho ‘<br>Scan compleat’
\necho ‘<\/center>’
\necho ‘<\/body>’
\necho ‘<\/html>’
\nfi<\/p>\n

——————————————————————————-<\/p>\n

Now let’s take a look at what that means:<\/p>\n

——————————————————————————-<\/p>\n

This time it wont be all the lines, but all the new parts:<\/p>\n

First the 2 variables:
\nmethod=`echo $QUERY_STRING | awk -F’=’ ‘{print $1}’`
\nhost=`echo $QUERY_STRING | awk -F’=’ ‘{print $2}’`<\/p>\n

These are made this way because of how the CGI script imports the variables
\nfrom a form (I’ll come back to this), the $QUERY_STRING variable is
\nfrom the webservers enviorment, and so is one of the httpds env variables.<\/p>\n

And what you do with the $QUERY_STRING is depending on how you create
\nyour web form …. but as I said I’ll get back to that.<\/p>\n

Now the rest:<\/p>\n

if [ “$method” = “nslookup” ]; then<\/p>\n

That was pretty obvious …. if the first feild of $QUERY_STRING (separated
\nby a =, is “nslookup”, then go ahead here:<\/p>\n

echo ‘Content-type: text\/html’
\necho ”<\/p>\n

Yes the header ….<\/p>\n

echo ‘<html>’
\necho ‘<body bgcolor=”white”>’
\necho ‘<center>’
\necho ‘<br>nslookup ‘$host’ (This might take a second)<br>’
\necho ‘<hr width=”100%”>’
\necho ‘<\/center>’
\necho ‘<pre>’<\/p>\n

Create a HTML page … and then after the <pre> we do the actual center part
\nof the script:<\/p>\n

nslookup $host<\/p>\n

Which will resolve the DNS of the host (try the command and see),
\nAnd after that we end the html page:<\/p>\n

echo ‘<\/pre>’
\necho ‘<center>’
\necho ‘<hr width=”100%”>’
\necho ‘<br>nslookup compleat’
\necho ‘<\/center>’
\necho ‘<\/body>’
\necho ‘<\/html>’<\/p>\n

and then end the if statement:<\/p>\n

fi<\/p>\n

and then the same for the others, just diffent objects at what they should
\ndo, as this was nslookup, the other sections will mnap (portscan) and ping
\nthe host instead.<\/p>\n

Now how would a full HTML page look to make use of this cgi script ?
\nAs we this time need input to get the host or IP to scan\/ping\/nmap.<\/p>\n

Well like this:<\/p>\n

——————————————————————————-<\/p>\n

<html>
\n<body bgcolor=”white”>
\n<center>
\n<p><font size=”+1″>Enter host or IP<\/font><\/p>
\n<hr width=”100%”>
\n<br>
\n<form action=”http:\/\/www.yourdomain.com\/cgi-bin\/scan.cgi<\/a>” method=”get”>
\n<input type=”text” name=”scan” value=”” size=”30″>
\n<input type=”submit” value=”portscan”>
\n<\/form>
\n<p>
\n<form action=”http:\/\/www.yourdomain.com\/cgi-bin\/scan.cgi<\/a>” method=”get”>
\n<input type=”text” name=”nslookup” value=”” size=”30″>
\n<input type=”submit” value=”nslookup”>
\n<\/form>
\n<p>
\n<form action=”http:\/\/www.yourdomain.com\/cgi-bin\/scan.cgi<\/a>” method=”get”>
\n<input type=”text” name=”ping” value=”” size=”30″>
\n<input type=”submit” value=”ping -c 5″>
\n<\/form>
\n<\/center>
\n<\/body>
\n<\/html><\/p>\n

——————————————————————————-<\/p>\n

Now what does all this mean ? ….
\nWell, I wont turn this into a HTML tutorial, but I’ll explain this so you
\ncan make use of bash for CGI.<\/p>\n

Right to the important HTML part here:<\/p>\n

<form action=”http:\/\/www.yourdomain.com\/cgi-bin\/scan.cgi<\/a>” method=”get”>
\n<input type=”text” name=”scan” value=”” size=”30″>
\n<input type=”submit” value=”portscan”>
\n<\/form><\/p>\n

Here we create a form, as in an input feild, which will add it’s input
\n(in a specific way) to the end of the url in action=””.
\nthe method is get since we’re getting the output of the cgi script.
\nwe name this feild scan so we get the output this way:
\n?scan=<input>
\nWhere the <input> is what you typed in the input box.
\nAnd then we make an “ok” button that says “portscan”.
\nSo if you type say 127.0.0.1 and press the portscan button the URL it will
\nbe directed to is this:<\/p>\n

http:\/\/www.yourdomain.com\/cgi-bin\/scan.cgi?scan=127.0.0.1<\/a><\/p>\n

And this “scan=127.0.0.1″ will be the $QUERY_STRING enviormental variable.<\/p>\n

And so the script is starting to make sense.<\/p>\n

——————————————————————————-<\/p>\n

Here’s a REALLY simple cgi script just for the illustration aswell.<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

string=”Hello World”<\/p>\n

echo ‘Content-type: text\/html’
\necho ”
\necho ‘<html>’
\necho ‘<br>’$string'<\/br>’
\necho ‘<\/html>’<\/p>\n

——————————————————————————-<\/p>\n

And the html to call that ….. just a normal hyper link.<\/p>\n

<a href=”http:\/\/www.yourdomain.com\/cgi-bin\/yourscript.cgi”>Link<\/a<\/a>><\/p>\n

And that’s it.<\/p>\n

——————————————————————————-<\/p>\n

That’s it on the tricks, now let’s move on to practical examples so you get
\na little bit of feel for how you can use bash to make things easier for you.<\/p>\n

===============================================================================
\n5 – Practical Scripting Examples.
\n===============================================================================<\/p>\n

I’d first like to add a note which you already probably knows:
\n.\/ == look in current directory instead of the “PATH”.
\nTo give that an example, say now that you have a script in your home
\ndirectory called “ls” or “dir”, how would you execute that without
\ngetting the contents of the directory ?
\nwell, that’s why you use “.\/”\u00a0 before a name to execute it if it’s in the
\ncurrent directory.
\n..\/ == previous directory (one directory further up towards “\/” then you are
\ncurrently in), this can be used as this, say that you have a script called
\n“script” in “\/home\/user\/” and you are standing in “\/home\/user\/nice\/” and
\nyou don’t want to leave the directory but still want to execute the script.
\nThen you do, “..\/script” and if you are in “\/home\/user\/nice\/blah\/” you
\nyou would do, “..\/..\/script” —– “..\/..\/” == 2 directory’s back.
\nGet the idea ?<\/p>\n

Anyway, now to the practical examples, which are working scripts for
\nvarious purposes, to give an idea about what you can do with shell scripting.
\nNew things previously not explained will show up in this section, but
\nI will explain them as we go along.<\/p>\n

Let’s start with simple examples and move on to harder parts.
\nAs for first I’ll stick to useless scripts =) just for illustration.
\nExplanation on the scripts follow after them, as usual.
\nSo here we go on that.<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

one=”$1″
\nsomething=”$2″<\/p>\n

if [ “$one” = “” ]; then
\necho “Usage: $0 [name] <anything goes here>”
\nexit 0
\nfi<\/p>\n

function first {
\nclear
\necho “this is a test script !”
\necho
\necho “name followed on $0 was – $one – ”
\necho
\necho “if you typed anything after the name it was: $something”
\necho
\n}<\/p>\n

first<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Executed without any thing after the script name it looks like this:<\/p>\n

alien:~$ .\/script
\nUsage: .\/script [name] <anything goes here>
\nalien:~$<\/p>\n

Executed with a name it looks like this:<\/p>\n

alien:~$ .\/script Jerry
\n—————————————-
\nthis is a test script !<\/p>\n

name followed on .\/script was – Jerry –<\/p>\n

if you typed anything after the name it was:<\/p>\n

alien:~$<\/p>\n

Executed with a name and something else it looks like this:<\/p>\n

alien:~$ .\/script Jerry homer
\n—————————————
\nthis is a test script !<\/p>\n

name followed on .\/script was – Jerry –<\/p>\n

if you typed anything after the name it was: homer<\/p>\n

alien:~$<\/p>\n

——————————————————————————-<\/p>\n

Notes: $0 == the script name’s variable so you can do a “Usage: <scriptname>”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 whatever the script is named after you made it.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 $1 == the first thing that’s typed after the script in the command line
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 $2 == the second thing that’s typed after the script in the command line
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 $3, $4 and so on …..<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 one=”$1″ this puts the contents of “$1” into the variable $one
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 which can be very useful to avoid errors.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 clear == clears the screen<\/p>\n

——————————————————————————-<\/p>\n

This next example is a script which you really shouldn’t use…
\nIt’s here as an example for a working help script, but *could*
\ncause harm if not used correctly.
\nSo if you loose anything because of using it, it’s all on you.
\nand don’t say I didn’t warn you.<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

if whoami | grep -v root >> \/dev\/null; then
\n\u00a0\u00a0\u00a0 echo “you have to be root to use this”
\n\u00a0exit 1
\nelse<\/p>\n

cat \/etc\/passwd | cut -f1 -d : | grep -v halt | grep -v operator | \\
\n\u00a0grep -v root | grep -v shutdown | grep -v sync | grep -v bin | \\
\n\u00a0grep -v ftp | grep -v daemon | grep -v adm | grep -v lp | \\
\n\u00a0grep -v mail | grep -v postmaster | grep -v news\u00a0 | grep -v uucp | \\
\n\u00a0grep -v man | grep -v games | grep -v guest | grep -v nobody > user.list
\nfi<\/p>\n

for USER in `cat user.list`; do
\n\u00a0if cat \/home\/$USER\/.bash_history | grep passwd >> \/dev\/null; then
\n\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0 echo “user $USER have tried to access the passwd file”
\n\u00a0\u00a0\u00a0 echo “do you want to remove $USER from your system [y\/n] ”
\nread YN
\n\u00a0if [ “$YN” = “y” ]; then
\n\u00a0\u00a0\u00a0 echo “user $USER is being deleted”
\n\u00a0\u00a0\u00a0 echo “home dir of user $USER is however intact”
\n\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0 remuser $USER
\n\u00a0else
\n\u00a0\u00a0\u00a0 echo “user $USER is not deleted”
\n\u00a0\u00a0\u00a0 echo
\n\u00a0fi
\nelse
\n\u00a0\u00a0\u00a0 echo “$USER haven’t tried to access the passwd file”
\n\u00a0fi
\ndone<\/p>\n

\u00a0rm user.list
\n\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0 echo “Script finished”
\n\u00a0\u00a0\u00a0 echo
\nexit 0<\/p>\n

——————————————————————————-<\/p>\n

I will just translate this script into real\/clear English:<\/p>\n

if (check own user-name) is anything else but root >> send output to a black hole
\nsay, “you have to be root to use this”
\nterminate program.
\nin other cases (in this case that can only be if the user is root)<\/p>\n

list the contents of the file “\/etc\/passwd” combined with – cut out the
\nuser names (field 1 separated by “:”) grep everything except lines containing the
\nfollowing words\/names: halt operator root shutdown sync bin ftp daemon
\nadm lp mail postmaster news uucp man games guest nobody and send it
\nto the file “user.list”
\nend “if” statement<\/p>\n

for each user in the “user.list” file do the following
\nif the word “passwd” is present in “\/home\/$USER\/.bash_history” >> output to
\nthe systems black hole
\nsay nothing
\nsay “user $USER haver tried to access the passwd file”
\nsay “do you want to remove $USER from your system [y\/n]”
\nread if the input from the keyboard is a “y” or “n”<\/p>\n

if the variable for the answer of the input is “y” then
\nsay “user $USER is being deleted”
\nsay “home dir of user $USER is however intact”
\nsay nothing
\nremoving the user from the system that tried to access the passwd file
\nin other cases
\nsay “user $USER is not deleted”
\nsay nothing
\nend “if” statement
\nin other cases
\nsay $USER haven’t tried to access the passwd file
\nend “if” statement
\nexit the for-loop<\/p>\n

remove the “user.list” file
\nsay nothing
\nsay “Script finished”
\nsay nothing<\/p>\n

exit and return to the shell command line.<\/p>\n

——————————————————————————-<\/p>\n

Note: grep -v == show everything *except* what comes after the -v<\/p>\n

——————————————————————————-<\/p>\n

Here is another way of doing the exact same script, just to illustrate that
\nthe same thing can be done in several different ways:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

if [ “$UID” != “0” ]; then
\n\u00a0\u00a0\u00a0 echo “you have to be root to use this”
\n\u00a0\u00a0\u00a0 exit -1
\nfi<\/p>\n

for uids in `cat \/etc\/passwd`; do
\n\u00a0\u00a0\u00a0 useruid=`echo “$uids” | awk -F’:’ ‘{print $(3)}’`
\n\u00a0\u00a0\u00a0 test “$useruid” -ge “500” 2>\/dev\/null &&
\n\u00a0\u00a0\u00a0 echo “$uids” | awk -F’:’ ‘{print $(1)}’ > user.list
\ndone<\/p>\n

for USER in `cat user.list`; do
\n\u00a0\u00a0\u00a0 if (grep passwd \/home\/$USER\/.bash_history >\/dev\/null); then
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “user $USER have tried to access the passwd file”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “do you want to remove $USER from your system [y\/n] ”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 read YN<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case $YN in
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 y* | Y*)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “user $USER is being deleted”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “home dir of user $USER is however intact”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 remuser $USER
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 n* | N*)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “user $USER is not deleted”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 esac
\n\u00a0\u00a0\u00a0 else
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “$USER haven’t tried to access the passwd file”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 rm -f user.list
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “Script finished”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0 fi
\ndone<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

Since this script does the exact same thing, but in another way, I’ll leav you
\nwith the experiance of trying to figure out the differences and how it
\nworks with the help of this tutorial, you might not get this right until
\nyou’ve read this tutorial twice.<\/p>\n

A tip is: try to make a comment to each line with what it does and why.<\/p>\n

——————————————————————————-<\/p>\n

This below script is a “Wingate” scanner, to scan for wingates that can
\nbe used to bounce off and such things, don’t know if that’s really legal
\nso take that on your own risk.<\/p>\n

Anyway here comes the script:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash
\necho > .log.tmp
\necho > .log2.tmp
\necho “sleep 7” > wg.config
\necho “killall -2 telnet” >> wg.config<\/p>\n

scan=”$1″
\ncount=”0″
\nmax=”255″<\/p>\n

clear<\/p>\n

if whoami | grep root >> \/dev\/null ; then
\n\u00a0\u00a0 echo “please use this as user and not root, since it would kill all users”
\n\u00a0\u00a0 echo “telnet sessions”
\n\u00a0else
\nclear
\nfi<\/p>\n

if [ “$1” = “” ]; then
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo ” usage is: $0 <C host> ”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo ”\u00a0 examples:”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo ”\u00a0 $0 127.0.0″
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo ” That will scan from 127.0.0.0 to 127.0.0.255″
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “be aware though, while it scans it also kills any other telnet”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “sessions you might have ….”
\n\u00a0exit 0
\nfi<\/p>\n

while [ “$count” != “$max” ]; do count=`expr $count + 1`
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo “Attempting connection to $1.$count ”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo > .log2.tmp
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .\/wg.config &
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 telnet $scan.$count >> .log.tmp
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 cat .log.tmp | grep -v refused | grep -v closed | grep -v Connected | grep -v Escape | grep -v login >> .log2.tmp
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo >> .log.tmp
\n\u00a0\u00a0\u00a0 done
\n\u00a0 echo “Script Finished, results stored in .log.tmp and .log2.tmp”
\nexit 0<\/p>\n

——————————————————————————-<\/p>\n

This time I will not translate the script into clear English and I will
\nnot show how it looks executed, I leave that for you to do =)<\/p>\n

——————————————————————————<\/p>\n

Now a final practical example of a script, this is a small graphical front end
\nto the console mp3 player `mpg123` so you got to have that to work
\nand you need to execute this script in a directly where you have mp3’s ….
\nAlso if you want the X-windows part of it to work you need to get and
\ninstall Xdialog, you can get that from www.freshmeat.net<\/a> …
\nHowever if you have Linux Mandrake you should be good anyway, Xdialog
\ncomes as default in Mandrake.
\nThis script should be named `xmpg123`.
\nSo here we go:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash
\ndialog –backtitle “xmpg123” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –title “Main menu” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –menu “Make your choice” 13 60 6 \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 “X-windows” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2 “Ncurses” \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3 “Exit” 2> .tempfile
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output=`cat .tempfile`
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo $output
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 rm -f .tempfile<\/p>\n

if [ “$output” = “1” ]; then
\nfor songs in `ls -1 *.mp3`; do
\necho “$songs mp3-file” >> .tempfile
\ndone
\noutput=`cat .tempfile`
\nXdialog –menu 2 2 2 1 $output\u00a0 \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2> .tempfile
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output=`cat .tempfile`
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 mpg123 $output
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 rm -f .tempfile
\nfi<\/p>\n

if [ “$output” = “2” ]; then
\nfor songs in `ls -1 *.mp3`; do
\necho “$songs mp3-file” >> .tempfile
\ndone
\nmenu=`cat .tempfile`
\ndialog –menu “Make your choice” 13 70 6 $menu 2> .tempfile
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output=`cat .tempfile`
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 mpg123 $output
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 rm -f .tempfile
\nfi<\/p>\n

exit 0<\/p>\n

——————————————————————————-<\/p>\n

A note being that dialog and Xdialog seems to be in early stages, so this
\nmay look sort of buggy if you don’t have the great dialog god at your side…<\/p>\n

——————————————————————————-
\n——————————————————————————-<\/p>\n

And don’t forget to “chmod u+x <script name> or chmod a+x <script name>
\nto make your scripts executable.<\/p>\n

===============================================================================
\n6 – Customize your system and shell.
\n===============================================================================<\/p>\n

This section is dedicated to how you can customize your system in various
\nways, this section was never planned to be in this tutorial, but since
\nI have received so many questions on how to do all this, I might as well
\ninclude it in the tutorial.<\/p>\n

——————————————————————————-<\/p>\n

First of I’m going to explain the local settings, this means the settings
\nthat will only affect a single user and not the whole ‘global’ system.
\nAnd the most logical way to start this is (I think) to talk about the shell.<\/p>\n

——————————————————————————-<\/p>\n

At the very top of this tutorial you will find the various types of shells,
\ndefault for most systems is \/bin\/bash, this is set in the \/etc\/passwd file
\nso a normal user can not change that.<\/p>\n

What a normal user can do if he wants to use another shell is to start it from
\nhis ~\/.bashrc file.
\nSo say now that you feel the urge to run tcsh, then just add the
\nline \/bin\/tcsh in your ~\/.bashrc, this may be done by doing:
\necho “\/bin\/tcsh” >> ~\/.bashrc
\npersonally I prefer the standard bash.<\/p>\n

But if you do have root (super user) access to the system, you can change
\nthe shell type correctly in the \/etc\/passwd file.<\/p>\n

here’s a user account with \/bin\/bash from \/etc\/passwd<\/p>\n

User:x:500:500:my real name:\/home\/user:\/bin\/bash<\/p>\n

And here the same line changed to \/bin\/tcsh (tenex C shell)<\/p>\n

User:x:500:500:my real name:\/home\/user:\/bin\/tcsh<\/p>\n

——————————————————————————-<\/p>\n

Here are the system variables you can use to change your enviorment,
\nthese can be set and exported from your ~\/.bash_profile or \/etc\/profile
\nIt’s not all of the\u00a0 variables but all the really interesting ones,
\nso here we go:<\/p>\n

BASH= this can also set your shell type, it’s most commonly defaulted
\n\u00a0to BASH=\/bin\/bash<\/p>\n

BASH_VERSION= this can change the version reply of bash, on my system
\n\u00a0 this is defaulted to BASH_VERSION=’2.03.19(1)-release’<\/p>\n

ENV=\u00a0 this should point to a file containing your enviorment,
\n\u00a0 this is by default: ENV=~\/.bashrc<\/p>\n

HISTFILE= this should point to a file that will contain your shell
\n\u00a0 ‘history’, as in your previously used commands.
\n\u00a0 this is by default set to: HISTFILE=~\/.bash_history<\/p>\n

HISTFILESIZE= the max aloowed size of the history file, usually around 1000<\/p>\n

HISTSIZE= about the same as HISTFILESIZE<\/p>\n

HOME=\u00a0 this should point to your home dir<\/p>\n

HOSTNAME= this is your hostname<\/p>\n

HOSTTYPE= this should return the same as the `arch` command.<\/p>\n

IFS=\u00a0 Internal Feild Separator …. this is a delimeter,
\n\u00a0 often defaulted to a new line as this:
\n……
\nIFS=’
\n‘
\n……<\/p>\n

INPUTRC= defaulted to INPUTRC=\/etc\/inputrc<\/p>\n

LANG=\u00a0 language variable, default is en for english<\/p>\n

LANGUAGE=\u00a0 about the same as LANG, also defaulted to en for english<\/p>\n

LINGUAS= defaulted to\u00a0 en_US:en\u00a0 also a language variable.<\/p>\n

LS_COLORS= sets colors to the `ls` command. this on my system
\n\u00a0 is defaulted to this:<\/p>\n

……
\nLS_COLORS=’no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:\\
\ncd=40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:\\
\n*.com=01;32:*.btm=01;32:*.bat=01;32:*.tar=01;31:*.tgz=01;31:*.tbz2=01;31:\\
\n*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lha=01;31:*.zip=01;31:\\
\n*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tz=01;31:*.rpm=01;31:\\
\n*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:*.xpm=01;35:\\
\n*.png=01;35:*.tif=01;35:*.tiff=01;35:’
\n……
\n\u00a0 So just add what you want here, and colors are the same
\n\u00a0 as explained about how to set the prompt later down, but
\n\u00a0 without the \u001b[ infront and m on the end.<\/p>\n

MAIL=\u00a0 mail file, usually MAIL=\/var\/spool\/mail\/<username><\/p>\n

OSTYPE=\u00a0 This can change your OS reply, it’s on a linux defaulted
\n\u00a0 to: OSTYPE=linux-gnu<\/p>\n

PATH=\u00a0 changes your path, this variable is explained in
\n\u00a0 the explanation of the \/etc\/profile file<\/p>\n

PPID=\u00a0 parent pid …. this is a read-only variable …
\n\u00a0 so you cant change it.<\/p>\n

PS1=\u00a0 the prompt variable, explained later down.<\/p>\n

PS2=\u00a0 the *more to come* variable, as if you type an unfinished
\n\u00a0 command string, it will bring you a new prompt where
\n\u00a0 you can finish it, this is usually defaulted to: PS2=’> ‘<\/p>\n

SHELL=\u00a0 another way to change your shell type …<\/p>\n

TERM=\u00a0 terminal type, usually defaulted to: TERM=linux
\n\u00a0 but can also be like: TERM=vt100
\n\u00a0 there are more video terminals then 100 though.<\/p>\n

UID=\u00a0 your user ID, if your root this will be 0,
\n\u00a0 this is a readonly variable.<\/p>\n

USER=\u00a0 your user name ….<\/p>\n

USERNAME= same as $USER<\/p>\n

Say that you want to change your shell to \/bin\/csh and your path to just \/bin
\n(you dont), but just if you would in your: .bash_profile add:<\/p>\n

——————————————————————————-<\/p>\n

SHELL=\/bin\/csh
\nPATH=\/bin<\/p>\n

export PATH SHELL<\/p>\n

——————————————————————————-<\/p>\n

Not so hard huh ?<\/p>\n

——————————————————————————-<\/p>\n

The next thing here is a question that I’ve heard alot, and that is “how do I
\nchange my command prompt ?”.<\/p>\n

The command Prompts variable is named PS1 ($PS1)<\/p>\n

for a prompt that looks like this:
\n[alien@localhost alien]$
\nthe contents of the PS1 variable would be this:
\n[\\u@\\h \\W]\\$<\/p>\n

All the prompts internal variables starts with a \\ (backslash)<\/p>\n

useful:<\/p>\n

\\$ = the prompt ($ for user and # for root)
\n\\d = date
\n\\h = abbreviated hostname (root.host.com would become root)
\n\\H = full hostname
\n\\s = shell type
\n\\t = time
\n\\T = time with seconds
\n\\u = username
\n\\v = shell version (short)
\n\\V = shell version (long)
\n\\w = full path
\n\\W = current directory name<\/p>\n

less useful:
\n\\e = erase rest of line …. not very useful
\n\\n = new line … not very useful
\n\\r = whatever comes after \\r is displayed before the first character.<\/p>\n

A couple of examples would be:<\/p>\n

*BSD like.
\nPS1=”\\u: \\w> ”<\/p>\n

DOS like.
\nPS1=”C:\\w > ”<\/p>\n

RedHat like.
\nPS1=”[\\u@\\h \\W]\\$ ”<\/p>\n

Init 1 like.
\nPS1=”\\s-\\v \\$ ”<\/p>\n

How do I use colors in the prompt ?<\/p>\n

To use colors in the prompt you need to be familiar with the escape sequence
\ncolor codings, those are as follows:<\/p>\n

reset\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0m
\nflashing\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[5m
\nblack\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;30m
\nred\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;31m
\ngreen\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;32m
\nyellow\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;33m
\nblue\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;34m
\nmagenta\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;35m
\ncyan\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;36m
\nwhite\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[0;37m
\nhighblack\u00a0\u00a0\u00a0\u00a0 = ^[[1;30m
\nhighred\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[1;31m
\nhighgreen\u00a0\u00a0\u00a0\u00a0 = ^[[1;32m
\nhighyellow\u00a0\u00a0\u00a0 = ^[[1;33m
\nhighblue\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[1;34m
\nhighmagenta\u00a0\u00a0 = ^[[1;35m
\nhighcyan\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[1;36m
\nhighwhite\u00a0\u00a0\u00a0\u00a0 = ^[[1;37m
\nbg-white\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[47m
\nbg-magenta\u00a0\u00a0\u00a0 = ^[[45m
\nbg-blue\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[44m
\nbg-red\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[41m
\nbg-black\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[40m
\nbg-green\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[42m
\nbg-yellow\u00a0\u00a0\u00a0\u00a0 = ^[[43m
\nbg-cyan\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = ^[[46m<\/p>\n

Important to know is that the leading `^[` is NOT 2 characters, it’s ONE
\ncontrol character that that takes up the space of 2 characters, or is
\ndescribed by 2 characters, if you have a real ^[ and you try to delete the
\n[ do it it will delete both the [ and the ^ at the same time.<\/p>\n

————————————————
\nNot really sure where to put this note but here,
\n^[[<number>G
\nPuts the cursor at column <number>, as this:<\/p>\n

echo -n “Starting myprog:” && echo -e “^[[50G OK” || echo -e “^[[50G FAILD”
\n————————————————<\/p>\n

So how do you get a real control character ?<\/p>\n

Either you use the very old line editor ‘ed’ and press Ctrl+[ to get the
\ncontrol character (ed commands are described at the end of this tutorial),
\nor you can use ’emacs’ or the text editor ‘joe’.<\/p>\n

To get control characters in emacs you press ^Q and ^<what you want>,
\nas if you want a ^[ you press ^Q^3, and then ^X^S^X^C to save and quit.<\/p>\n

To get control characters in joe you press ` and then the character to make
\na control character, in this case [, when you do this in joe the ^[
\nshould look like a bold [.
\nTo save and quit in joe you press: Ctrl+K followed by Ctrl+X<\/p>\n

It’s only the ^[ that is a control character the rest is normal [‘s and
\nnumbers and so on.<\/p>\n

Don’t forget to enclose all your colors codes in \\[ \\], this means that
\n^[[0;31m (red) would be written as \\[^[[0;31m\\].<\/p>\n

Where do I write this and how does an example look ?<\/p>\n

You add this in your ~\/.bash_profile, you can put it at the end of the file.<\/p>\n

Some examples are:<\/p>\n

[ highblue-user red-@ highblue-host green-dir ] highblue-$
\nPS1=”\\[^[[1;34m\\u^[[0;31m@^[[1;34m\\h ^[[0;32m\\W^[[0m\\]^[[1;34m\\$ \\[^[[0m\\] ”<\/p>\n

highblue-user highwhite-: highblue-path >
\nPS1=”\\[^[[1;34m\\]\\u\\[^[[1;37m\\]: \\[^[[0;31m\\]\\w \\[^[[0m\\]> ”<\/p>\n

(you can not cut and paste these examples without editing the ^[‘s to real
\ncontrol characters, and know that a color prompt is almost always buggy)<\/p>\n

——————————————————————————-<\/p>\n

The next thing to take up is how to set aliases and to change system variables.<\/p>\n

An alias is set in the ~\/.bashrc file, if you use \/bin\/bash else, it’s most
\nlikely in your .`shell type`rc as .zshrc .csh .tcsh etc.<\/p>\n

An alias means that you can make a short command for a longer command,
\nas the alias `l` can mean `ls` and the alias `la` can mean `ls -la`, and
\nso on, an alias is written like this (also a list of useful aliases):<\/p>\n

alias rm=’rm -i’
\nalias mv=’mv -i’
\nalias cp=’cp -i’
\nalias s=’cd ..’
\nalias d=’ls’
\nalias p=’cd -‘
\nalias ll=’ls -laF –color’
\nalias lsrpm=’rpm -qlp’
\nalias lstgz=’tar -tzf’
\nalias lstar=’tar -tf’
\nalias mktgz=’tar -cfz’
\nalias untar=’tar -vxf’
\nalias untgz=’tar -vzxf’<\/p>\n

rm will now ask before removing anything.<\/p>\n

mv will now ask before overwriting anything.<\/p>\n

cp will now ask before overwriting anything.<\/p>\n

s will now work as cd ..<\/p>\n

d will now work as ls.<\/p>\n

p will now work as cd – (cd – == takes you to your last dir ie.
\nyou are in \/usr\/local\/bin\/ and does a cd \/, if you from here wanna go back
\nto \/usr\/local\/bin\/ you simply type `cd -`, or now just `p`.)<\/p>\n

ll will do a ls -la with colors and ending * after executable files and ending
\nan ending \/ after dirs.<\/p>\n

lsrpm will list the contents (where the files will end up if you install it) of
\nany rpm file.<\/p>\n

lstgz will list the contents of a .tar.gz or .tgz file.<\/p>\n

lstar will list the contents of a plain .tar file.<\/p>\n

mkgz will make a tgz archive (mktar archive.tgz directory).<\/p>\n

untar will untar a .tar file.<\/p>\n

untgz will unzip and untar a\u00a0 .tar.gz or a .tgz file.<\/p>\n

There is more alias like things you can set in the ~\/.bashrc file, like
\nsmaller functions that works as aliases, like this:<\/p>\n

function whichrpm { rpm -qf `’which’ $1`; }<\/p>\n

typing “whichrpm <command>” at a prompt will name the rpm file it came with.<\/p>\n

the rpm -qf command works like this:<\/p>\n

alien:~$ rpm -qf \/usr\/bin\/dir
\nfileutils-4.0i-1mdk
\nalien:~$<\/p>\n

And the function works like this:<\/p>\n

alien:~$ whichrpm dir
\nfileutils-4.0i-1mdk
\nalien:~$<\/p>\n

function – tells bash that it’s function.
\nwhichrpm – user defined name of the function.
\n{ \/ } – starts\/ends the function
\nrpm -qf – command
\n` command quote
\n‘ precise quote
\nwhich – command to locate a file in your path
\n$1 – first argument after the function (the command after the function name
\nwhen you execute it).
\n; – end line
\nfunction whichrpm { rpm -qf `’which’ $1`; }<\/p>\n

So when you execute this, the system will think.
\naaah, a function within those {}’s, which I should call for when I hear
\nthe word “whichrpm”, and what’s after that word ($1) will be used as
\nargument to “which”, and what that returns will be used after “rpm -qf”.<\/p>\n

which works like this:<\/p>\n

alien:~$ which dir
\n\/usr\/bin\/dir
\nalien:~$<\/p>\n

So “`’which’ $1`” (when executed with the word ‘dir’) returns “\/usr\/bin\/dir”,
\nand so the whole function will finally execute: rpm -qf \/usr\/bin\/dir<\/p>\n

——————————————————————————-<\/p>\n

Now more about the files in \/etc, here you cant be user anymore,
\nto edit the files in \/etc requires you to be root.<\/p>\n

Fist here I’m going to talk about the \/etc\/crontab configuration file.<\/p>\n

——————————————————————————-<\/p>\n

The \/etc\/crontab is the global system file for cron jobs.
\ncron is short for chronological, and as the name tells it’s doing things
\nin a chronological order, as you can tell it to run a script or a program
\nonce every 1 minutes, or you can tell it to run something annually, and
\nanything in between.<\/p>\n

On RedHat like systems you have the dirs:<\/p>\n

\/etc\/cron.daily\/
\n\/etc\/cron.hourly\/
\n\/etc\/cron.monthly\/
\n\/etc\/cron.weekly\/<\/p>\n

Any script or program that lives in those files will execute by the last
\nname of the file, as if you put a script in \/etc\/cron.weekly\/, the script
\nwill execute weekly.<\/p>\n

The \/etc\/crontab looks like this:<\/p>\n

SHELL=\/bin\/bash
\nPATH=\/sbin:\/bin:\/usr\/sbin:\/usr\/bin
\nMAILTO=root
\nHOME=\/<\/p>\n

# run-parts
\n01 * * * * root run-parts \/etc\/cron.hourly
\n02 4 * * * root run-parts \/etc\/cron.daily
\n22 4 * * 0 root run-parts \/etc\/cron.weekly
\n42 4 1 * * root run-parts \/etc\/cron.monthly<\/p>\n

The SHELL determens what shell that should be used to execute the things
\nin the crontab.<\/p>\n

The PATH determens what directory’s it should look in for commands\/programs
\nif no other specific path is given to a program, command or script.<\/p>\n

The MAILTO variable determens to what user cron should send mails to on errors.<\/p>\n

And the HOME variable determens crons root\/home\/base directory.<\/p>\n

The first 5 fields determens when to run a job, here’s what they mean:<\/p>\n

Field 1: minutes (0-59)
\nField 2: hours (0-23)
\nField 3: day of month (1-31)
\nField 4: month (1-12 – or names)
\nField 5: weekday (0-7 – 0 or 7 is Sun, or use names)<\/p>\n

The next field is the user that owns the execution process.<\/p>\n

Then we have run-parts, and after that the file to execute.
\n(if the file to execute is a dir, it will execute everything in it)<\/p>\n

To use the crontab as a user (root included) simply type: crontab -e
\nThis brings you to a VI like editor (see VI commands later in this tutorial).
\nSay now that you have a script \/home\/user\/check.sh that you wanna run
\nevery 5’th minute. then you type “crontab -e”
\nPress ‘Esc’ followed by ‘o’ to get to “insert” or “edit” mode.
\nIn there make the following line:<\/p>\n

0,5,10,15,20,25,30,35,40,45,50,55 * * * *\u00a0 \/home\/user\/check.sh –flag<\/p>\n

Then press ‘Esc’ followed by ‘:’ and then type ‘wq’ followed by enter to
\nwrite\/save and, quit the file, and that’s it.<\/p>\n

When you run crontab as user you don’t have to specify what user that should
\nown the process, “* * * * * file” should be enough.<\/p>\n

Another way of writing:
\n0,5,10,15,20,25,30,35,40,45,50,55 * * * *\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/home\/user\/check.sh –flag
\nIs this:
\n0-59\/5 * * * *\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/home\/user\/check.sh –flag
\nThat means do this (\/home\/user\/check.sh –flag) from 0-59 with 5 as an
\nintervall.
\nThis means that:
\n* 0-23\/2 * * *\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/home\/user\/check.sh –flag
\nWould run the same script every other hour.<\/p>\n

Not very hard is it ?<\/p>\n

——————————————————————————-<\/p>\n

Then we have the\u00a0 \/etc\/fstab is a list of the HD partitions the system
\nshould mount as what when the system boots.
\nThis may look like this:<\/p>\n

\/dev\/hda1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ext2\u00a0\u00a0\u00a0 defaults\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 1
\n\/dev\/hda3\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 none\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 swap\u00a0\u00a0\u00a0 sw\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0 0
\n\/dev\/hda4\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/home\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ext2\u00a0\u00a0\u00a0 defaults\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 2
\n\/dev\/hda6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/tmp\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ext2\u00a0\u00a0\u00a0 defaults\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 2
\n\/dev\/hdc1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/windows\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 vfat\u00a0\u00a0\u00a0 defaults\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0 0
\n\/dev\/fd0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/mnt\/floppy\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 auto\u00a0\u00a0\u00a0 noauto,nosuid\u00a0\u00a0 0 0
\n\/dev\/hdb\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/mnt\/cdrom\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 auto\u00a0\u00a0\u00a0 noauto,ro\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0 0<\/p>\n

Fist it’s the HD partition, then (a few tabs in) the mount point (where the
\neventual contents of the HD partition should end up), then what file system
\nthe partition has, further is if it should be mounted by default etc.
\nand the last 2 numbers is fs_freq and fs_passno (see the man page for fstab).<\/p>\n

The possible HD partitions you have to find for your self or know…
\na tip is to go over the HD’s with fdisk, and check for free space.<\/p>\n

The possible mount points is only limited by your imagination, though
\nthere must always be a \/
\nA good disk usage should have these partitions:
\n\/ 5%
\n\/usr 30%
\n\/home 30%
\n\/tmp 10%
\nAnd 25% over for other partitions, like \/sources, or whatever.<\/p>\n

The possible and supported file systems are currenty:
\nminix,ext,ext2,xiafs,msdos,hpfs,iso9660,nfs,swap,vfat, and perhaps ntfs<\/p>\n

The possible mount options are:
\nsync,user,noauto,nosuid,nodev,unhide,user,noauto,nosuid,exec,nodev,ro etc.
\nsee the man mount page.<\/p>\n

So say that you are going to add another cdrom that you want user to be able
\nto mount, and the cdrom is on \/dev\/hdd, then the line to add would look like
\nthis (make sure you have the mount point dir, like here you have to
\nmkdir \/cdrom):<\/p>\n

\/dev\/hdd\u00a0 \/cdrom\u00a0\u00a0 auto noauto,user,ro 0 0<\/p>\n

And that’s about it for the \/etc\/fstab<\/p>\n

——————————————————————————-<\/p>\n

Now I’d like to explain one of the very important files, the \/etc\/profile file.
\nIn this file is the Global profile settings, that will apply for all users.<\/p>\n

Fist in this file we should have the PATH variable.
\nThe directory’s in the PATH is the directory’s the system will look in if you
\ntype a command, for that command to execute it.<\/p>\n

Say now that your path looks like this:
\nPATH=”$PATH:\/usr\/X11R6\/bin:\/bin”<\/p>\n

And you type “ls”, then the system will first look in \/usr\/X11R6\/bin if it can
\nfind any file named “ls”, and if it doesn’t find it there, it will look in \/bin,
\nand if it finds it there it will execute it.<\/p>\n

The most common places on a system to store commands and programs is in these
\ndirectory’s:
\n\/usr\/X11R6\/bin
\n\/bin
\n\/sbin
\n\/usr\/bin
\n\/usr\/sbin
\n\/usr\/local\/bin
\n\/usr\/local\/sbin<\/p>\n

A path with all those directory’s in it would look like this:
\nPATH=”$PATH:\/usr\/X11R6\/bin:\/bin:\/sbin:\/usr\/local\/bin:\/usr\/local\/sbin:\/usr\/bin:\/usr\/sbin”<\/p>\n

The next thing in there can\/should be the PS1 (the prompt), I’ve already
\ntaken up how to customize the prompt, so no need to do that again.<\/p>\n

Then (at least in RedHat like systems) we have this:<\/p>\n

[ “$UID” = “0” ] && {
\nulimit -c 1000000
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 } || {
\nulimit -c 0
\n}<\/p>\n

This says: if the UID of the user is 0 (root) then do: ulimit -c 1000000
\nor if that doesn’t work, do: ulimit -c 0.<\/p>\n

Then we have an if statement about umask on the user…<\/p>\n

After that we define some system variables, where after we export them.<\/p>\n

Then we load all the .sh scripts in \/etc\/profile.d\/<\/p>\n

And that’s it, in that file.<\/p>\n

This is an important file if you wanna add any system variables, or if you
\nwant to change anything globally for the whole system.<\/p>\n

——————————————————————————-<\/p>\n

Now on to the \/etc\/hosts.allow and \/etc\/hosts.deny files.<\/p>\n

Those hosts who are in hosts.allow are always allowed to connect to the system
\nunder the condition that they have valid login and password ofcorse.<\/p>\n

Those hosts who are in hosts.deny can never establish a lasting connection
\nto your system, even if they have a valid login and password.<\/p>\n

If you don’t want anyone to connect to your computer at all, you simply add
\nthe following to \/etc\/hosts.deny:<\/p>\n

ALL: ALL<\/p>\n

And this to \/etc\/hosts.allow:<\/p>\n

ALL: LOCAL<\/p>\n

Or if you have a network, you may wanna add this in \/etc\/hosts.allow:<\/p>\n

ALL: LOCAL, 192.168.1.<\/p>\n

Where 192.168.1. is your network call C network.<\/p>\n

\/etc\/hosts.allow and \/etc\/hosts.deny understands the following wildcards:<\/p>\n

ALL\u00a0\u00a0\u00a0\u00a0\u00a0 The universal wildcard, always matches.
\nLOCAL\u00a0\u00a0\u00a0 Matches\u00a0 any host whose name does not contain a dot character.
\nUNKNOWN\u00a0 Matches any user whose name is unknown.
\nKNOWN\u00a0\u00a0\u00a0 Matches any user whose name is known.
\nPARANOID Matches any host whose\u00a0 name\u00a0 does\u00a0 not\u00a0 match\u00a0 its address.<\/p>\n

Read man hosts.allow or man hosts.deny (should be the same man file), to find
\nout more about this.<\/p>\n

——————————————————————————-<\/p>\n

Next up is the \/etc\/inputrc file, which contains breaf keyboad confirurations.
\nIf you want to something like Ctrl+W or something to a function of any kind
\nhere is the place to do that.
\nThe example from the file looks like this:<\/p>\n

# Just a little exemple, how do you can configure your keyboard
\n# If you type Control-x s it’s add a su -c ” ” around the command
\n# See the info files (readline) for more details.
\n#
\n# “\\C-xs”: “\\C-e\\”\\C-asu -c \\””<\/p>\n

This would mean that if you want to add say: Ctrl+W to add the command
\n`time` before another command you would do:<\/p>\n

“\\C-w”: “\\C-e\\ \\C-atime \\<\/p>\n

Another example would be, if you want to add: Ctrl+W Q to add: echo “<command>”
\naround the <command> you would do:<\/p>\n

“\\C-wq”: “\\C-e\\”\\C-aecho \\””<\/p>\n

This means that if you type ‘word’ and then press Ctrl+W followed by Q you
\nwill end up with: echo “word”, pretty handy.<\/p>\n

You can also add a .inputrc in your home dir with the same functions,
\nbut only for that user.<\/p>\n

Just make sure you dont overwrite some other function, test the Ctrl+<key(s)>
\nfunction that you wanna use so they dont already do something.<\/p>\n

If you want to bind keys to functions or characters, this is not the place
\nto do that, then you need to find your keymap like this one:
\n\/usr\/lib\/kbd\/keymaps\/i386\/qwerty\/se-latin1.kmap.gz
\ngunzip it, edit it and then zip it up again.<\/p>\n

I will not explain how to edit a keymap here, but it’s not that hard,
\njust read the contnts of the unziped keymap a few times and use the
\npower of deduction.<\/p>\n

——————————————————————————-<\/p>\n

The \/etc\/passwd holds the login information which looks something like this:<\/p>\n

root:x:0:0:root:\/root:\/bin\/bash
\nbin:x:1:1:bin:\/bin:
\ndaemon:x:2:2:daemon:\/sbin:
\nadm:x:3:4:adm:\/var\/adm:
\nlp:x:4:7:lp:\/var\/spool\/lpd:
\nshutdown:x:6:0:shutdown:\/sbin:\/sbin\/shutdown
\nalien:x:500:500:Me:\/home\/alien:\/bin\/bash
\nuser:x:501:501::\/home\/user:\/bin\/csh<\/p>\n

You are looking on 7 accounts, nameley: root, bin, daemon, adm, lp, shutdown,
\nalien and user.<\/p>\n

each of the lines have 7 feilds separated by ‘:’.
\nThe fields from left to right are:<\/p>\n

1 login-name
\n2 encrypted-password (this field contains only ‘x’ if there is an \/etc\/shadow)
\n3 uid (user id)
\n4 gid (group id)
\n5 user-information
\n6 home-directory
\n7 shell-type<\/p>\n

If you make an account by hand in the \/etc\/passwd file, put a ‘*’ in the
\nencrypted-password field and use the `passwd` command to set the password.<\/p>\n

——————————————————————————-<\/p>\n

The \/etc\/shadow file, if this file exists, this is where the real
\nencrypted passwords are located, this file can only be read by the super-user
\n(root), and it looks like this:<\/p>\n

root:$1$UrbUdguK$yrO3U\/dlwKC5K3y2ON\/YM.:11056:0:21:7:::
\nbin:*:11056:0:99999:7:::
\ndaemon:*:11056:0:99999:7:::
\nadm:*:11056:0:99999:7:::
\nlp:*:11056:0:99999:7:::
\nshutdown:$1$hu86lnLIhnklY8ijnHui7.nn\/jYg\/mU:11056:1:365:14:::
\nalien:$1$vf3tGCFF$YRoFUgFDR8CVK6hHOwU\/p0:11056:0:50:14:31::
\nuser:$1$asd8kiLY76JNdskDkj97kMiyBujy\/jD:11074:2:100:14:3::<\/p>\n

(I’ve changed the characters in the encrypted-password, so they are not valid)<\/p>\n

The manual page (man 5 shadow) tells the following about the 9 fields:<\/p>\n

Login name
\nEncrypted password
\nDays since Jan 1, 1970 that password was last changed
\nDays before password may be changed
\nDays after which password must be changed
\nDays before password is to expire that user is warned
\nDays after password expires that account is disabled
\nDays since Jan 1, 1970 that account is disabled
\nA reserved field<\/p>\n

If anyone knows what the last field (after the final ‘:’) is reserved for …
\nplease drop me a mail.<\/p>\n

Read the lines from the files, and compare them with what the 9 fields
\nmean, and see if you can make out how the accounts for each user is set up.<\/p>\n

——————————————————————————-<\/p>\n

Now the \/etc\/motd file.<\/p>\n

The \/etc\/motd contains whatever you want to display to the user
\nthat logs into the system, this can be a set of rules for your system,
\nor some ascii graphics or whatever you want.<\/p>\n

——————————————————————————-<\/p>\n

And now the \/etc\/skel\/ which is a dir and contains the basic files
\nthat will be given to any new user account.<\/p>\n

Say that you add a file called, \/etc\/skel\/.ircrc then all new useraccounts
\nthat are added will have a ~\/.ircrc file in there home directory.<\/p>\n

——————————————————————————-<\/p>\n

And last the \/etc\/issue and \/etc\/issue.net file.
\nOn most systems there is only an \/etc\/issue file that works as both
\n\/etc\/issue and \/etc\/issue.net, the issue file holds the information
\nor rather text that is displayed to the user just before the
\nlogin prompt, usually it is the system specifications, like operating system
\nversion and things like that.<\/p>\n

The \/etc\/issue (if there is any \/etc\/issue.net) is the issue file for the
\nlocal users, and the \/etc\/issue.net is for users that logs in
\nfrom a remote host.<\/p>\n

——————————————————————————-<\/p>\n

There is alot more in the \/etc directory, but what I’ve written this
\nfar is about what you need to customize your system to your needs.<\/p>\n

===============================================================================
\n7 – Networking.
\n===============================================================================<\/p>\n

Linux is known to be one of the best networking operating systems in the
\nworld, perhaps even THE best, unfortionally it’s not the easiest OS to
\nset up a good network in, but I hope that this section will make
\nexclamation marks out of some question marks.<\/p>\n

——————————————————————————-<\/p>\n

The first thing you need to do networking is 2 computers and
\nnetwork cards attached with a crossed network cable, or connected via a hub,
\nwith normal network cable (doh?).<\/p>\n

The next step is to make sure the network cards work properly.<\/p>\n

Make sure you have the networking support compiled into the kernel, you need
\nto have the following checked in the kernel (example is from the Linux 2.2.14
\nkernel, using `make menuconfig`, you can read more about how you
\ncompile\/recompile your kernel in \/usr\/doc\/HOWTO\/Kernel-HOWTO):<\/p>\n

General setup\u00a0 —>
\n\u00a0[*] Networking support
\nNetworking options\u00a0 —>
\n\u00a0[*] Kernel\/User netlink socket
\n\u00a0[*] Network firewalls
\n\u00a0<*> Unix domain sockets
\n\u00a0[*] TCP\/IP networking
\n\u00a0[*] IP: advanced router
\n\u00a0[*] IP: firewalling
\n\u00a0[*] IP: transparent proxy support
\n\u00a0[*] IP: masquerading
\n\u00a0[*] IP: ICMP masquerading
\n\u00a0[*] IP: aliasing support
\n\u00a0<*> IP: Reverse ARP
\n\u00a0[*] IP: Allow large windows (not recommended if <16Mb of memory)
\nNetwork device support\u00a0 —>
\n\u00a0[*] Network device support
\n\u00a0Ethernet (10 or 100Mbit)\u00a0 —>
\n\u00a0 [*] Ethernet (10 or 100Mbit)
\n\u00a0 (In here find your network card and check it.)
\nFilesystems\u00a0 —>
\n\u00a0[*] \/proc filesystem support<\/p>\n

Then you add this line in your \/etc\/rc.d\/rc.local<\/p>\n

echo “1” > \/proc\/sys\/net\/ipv4\/ip_forward () at boot time<\/p>\n

——————————————————————————-<\/p>\n

If you have more then one network card, you may wanna add one as Module and
\none hard compiled (*) into the kernel, so that the kernel knows that it’s
\n2 network cards.<\/p>\n

Then you need to name then eth0 and eth1, this you *may* have to do
\neven if you only have 1 network card, but it’s not likely.<\/p>\n

I have 2 network cards, one “3com 509 B” and one “3com 905”
\nThe first thing I need to do is to is to find the module name for
\nthe network cards.
\nGo to \/lib\/modules\/2.2.14\/misc\/ and do an “ls”
\n(the 2.2.14\/ dir will be named after whatever kernel version you have,
\n`uname -r` to find out)
\nIn there I found a file called 3c59x.o (that’s the one I compiled as module),
\nthen I set that as eth0, like this:
\nI open the file \/etc\/conf.modules (or \/etc\/modules.conf depending on the
\nkernel and\u00a0 system) and add:<\/p>\n

alias eth0 3c59x<\/p>\n

Then I know the other card is a “3com 509 B” so I go to:
\n\/lib\/modules\/2.2.14\/net\/ and in there I find a 3c509.o, so I again
\nadd an alias in \/etc\/conf.modules:<\/p>\n

alias eth1 3c509<\/p>\n

Basicly, you will find the network cards you added from the kernel in either
\n\/lib\/modules\/2.2.14\/net\/ or \/lib\/modules\/2.2.14\/misc\/, or say now
\nthat you had a Linux 2.2.15 kernel then it would be:
\n\/lib\/modules\/2.2.15\/net\/ and \/lib\/modules\/2.2.15\/misc\/<\/p>\n

And remember to add the cardnames without the .o in the module name, as
\n3c509.o will be named 3c509 as an alias in \/etc\/conf.modules.<\/p>\n

——————————————————————————-<\/p>\n

Now you wanna add the network card so it starts at boot time and get an IP.
\nNow you must decide what network IP it should have
\n(either 192.168.1.* or 10.0.0.* in this example I’ve used 10.0.0.*)
\nOpen or crate a file called: \/etc\/sysconfig\/network-scripts\/ifcfg-eth0
\n(if it doesn’t exist when you open it it will be created.)<\/p>\n

In this file type the following:<\/p>\n

ONBOOT=yes
\nDEVICE=eth0
\nIPADDR=10.0.0.1
\nNETMASK=255.255.255.0
\nNETWORK=10.0.0.0
\nBROADCAST=10.255.255.255
\nBOOTPROTO=none<\/p>\n

The save and quit.<\/p>\n

ifcfg-eth0 goes if this is your first network card, if it were your second
\nnetwork card on the same computer it would be ifcfg-eth1, and then the
\nDEVICE variable would say DEVICE=eth1.<\/p>\n

——————————————————————————-<\/p>\n

After this you need to tell your computer what IP, network name and nick name
\nit has. This you do in \/etc\/hosts.
\nBy default you should have this line in your \/etc\/hosts:<\/p>\n

127.0.0.1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 localhost\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 localhost.localdomain<\/p>\n

Now you add your new hosts, the current computer and the other computer(s),
\nhere I have used the 10.0.0.* IP range.<\/p>\n

10.0.0.1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 main.bogus.com main
\n10.0.0.2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 sidekick.bogus.com sidekick<\/p>\n

Note that there is a TAB separating each of the 3 fields (IP hostname nick).<\/p>\n

——————————————————————————-<\/p>\n

After that it’s time to set up the forwarding and everything like that using
\nipchains.
\nThis you do by adding the following lines to your \/etc\/rc.d\/rc.local<\/p>\n

\/sbin\/ipchains -P forward DENY
\n\/sbin\/ipchains -A forward -i eth0 -j MASQ<\/p>\n

You may also wanna execute the lines since \/etc\/rc.d\/rc.local only
\nloads at boot time.<\/p>\n

——————————————————————————-<\/p>\n

At this time you may also wanna set up a caching nameserver on your system,
\nBoth to speed up your surfing and to get your LAN (Local Area Network)
\nto interact in a proper way.<\/p>\n

In the following example I’ve used:<\/p>\n

bind-8.2.2P5-1mdk.i586.rpm
\nand
\ncaching-nameserver-6.0-3mdk.noarch.rpm<\/p>\n

(A nameserver is depending on bind)<\/p>\n

So after you installed bind and a caching-nameserver this is what you wanna do,
\n(everything in this example is based on the previously written network
\nconfigurations):<\/p>\n

First you need to edit a file named \/etc\/named.conf, where in you add a “zone”.
\nThe zones in this example to add, looks like this:<\/p>\n

zone “bogus.com” {
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 type master;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 file “bogus.com”;
\n};<\/p>\n

zone “0.0.10.in-addr.arpa” {
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 type master;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 file “10.0.0”;
\n};<\/p>\n

The first one is for the networked computers hostnames, and the second for
\nthere IP’s.<\/p>\n

In this example I use 10.0.0.* as the network IP, but another common network
\nIP is also 192.168.0.* …. those are the two most common\/accepted ones.<\/p>\n

Then you save and quit that, to go and create the files bogus.com and 10.0.0,
\nwhich you do in: \/var\/named\/<\/p>\n

First we can create \/var\/named\/bogus.com, and in there type the following:<\/p>\n

@\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 IN\u00a0\u00a0\u00a0\u00a0\u00a0 SOA\u00a0\u00a0\u00a0\u00a0 ns.bogus.com. main.bogus.com.\u00a0 (
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2000020100 ; Serial
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 28800\u00a0\u00a0\u00a0\u00a0\u00a0 ; Refresh
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 14400\u00a0\u00a0\u00a0\u00a0\u00a0 ; Retry
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3600000\u00a0\u00a0\u00a0 ; Expire
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 86400 )\u00a0\u00a0\u00a0 ; Minimum
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 IN\u00a0\u00a0\u00a0\u00a0\u00a0 NS\u00a0\u00a0\u00a0\u00a0\u00a0 localhost.
\n\u00a0\u00a0\u00a0\u00a0\u00a0 ;1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 IN\u00a0\u00a0\u00a0\u00a0\u00a0 PTR\u00a0\u00a0\u00a0\u00a0 localhost.
\nlocalhost\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 127.0.0.1
\nns\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 10.0.0.1
\nsidekick\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 10.0.0.2
\nmain\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 10.0.0.1
\nmail\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 10.0.0.1<\/p>\n

(What comes before the Serial, 2000020100 is a date, 2000-02-01-00, so
\nyou can type that as your current date.)<\/p>\n

Then you save and quit that, and crate the file: \/var\/named\/10.0.0, and in
\nthere you type this:<\/p>\n

@\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 IN\u00a0\u00a0\u00a0\u00a0\u00a0 SOA\u00a0\u00a0\u00a0\u00a0 ns.bogus.com. main.bogus.com.\u00a0 (
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2000020100 ; Serial
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 28800\u00a0\u00a0\u00a0\u00a0\u00a0 ; Refresh
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 14400\u00a0\u00a0\u00a0\u00a0\u00a0 ; Retry
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3600000\u00a0\u00a0\u00a0 ; Expire
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 86400 )\u00a0\u00a0\u00a0 ; Minimum
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NS\u00a0\u00a0\u00a0\u00a0\u00a0 ns.bogus.com.
\n1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 PTR\u00a0\u00a0\u00a0\u00a0 main.bogus.com.
\n2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 PTR\u00a0\u00a0\u00a0\u00a0 sidekick.bogus.com.<\/p>\n

Now it’s almost time to start the nameserver, but first you wanna add the
\nnameserver to your \/etc\/resolv.conf so you have any use of it.<\/p>\n

Open \/etc\/resolv.conf and at the top of it add:<\/p>\n

nameserver 10.0.0.1<\/p>\n

and leav the rest of the file entry’s as they are if there is any, then
\nsave and quit that.<\/p>\n

And now it’s time to start the nameserver.
\nTo be sure that everything works normally, do these commands:<\/p>\n

\/usr\/sbin\/named
\n\/usr\/sbin\/ndc restart<\/p>\n

And then type `nslookup`, that should look like this:<\/p>\n

root:~# nslookup
\nDefault Server:\u00a0 main.bogus.com
\nAddress:\u00a0 10.0.0.1<\/p>\n

><\/p>\n

If you get that, just type exit at the “>”, and then add the following lines
\nto \/etc\/rc.d\/rc.local<\/p>\n

if
\nps aux | grep named | grep -v grep >\/dev\/null ; then
\necho >\/dev\/null
\nelse
\n\/usr\/sbin\/named
\n\/usr\/sbin\/ndc restart
\nfi<\/p>\n

This will check if you have a named running, and if not, it will start it,
\nnote that this is not the 100% correct way to do it, but it’s by far they
\nmost lazy way to do it, and it works.<\/p>\n

——————————————————————————-<\/p>\n

That was the basics of making a network at home and setting up a nameserver.
\nI hope it’s enough so that anyone can set up a little network at home.<\/p>\n

===============================================================================
\n8 – The Init and system scripts.
\n===============================================================================<\/p>\n

In this section I will cover the system V init, which is the most used
\ninit in Linux.
\nBeside the Syst V inti, there are also the BSD init, which is used by
\nSlackware and Debian and in some smaller distributions of Linux.
\nThe rest, as far as I know, uses the Syst V init.
\nThere are not so much difference of the two, I’ll try to cover the
\ndifferences later.
\nThe example and files here are taken from SysVinit-2.78-6 & initscripts-5.27-37
\nwhich is compatible in some ways with the BSD init, I’ll come back to that
\nlater.<\/p>\n

So here we go:<\/p>\n

——————————————————————————-<\/p>\n

The basic Syst V init comes with the following commands & devices:<\/p>\n

\/dev\/initctl\u00a0 This is the init controll device.
\n\/sbin\/halt\u00a0 This is to shut down the system.
\n\/sbin\/init\u00a0 This is to change the init runlevel.
\n\/sbin\/killall5\u00a0 This will kill everything but the script that runs it.
\n\/sbin\/pidof\u00a0 This will get the PID of a Process name.
\n\/sbin\/poweroff\u00a0 This will power down the system.
\n\/sbin\/reboot\u00a0 This will reboot the system.
\n\/sbin\/runlevel\u00a0 This will tell the init runlevel.
\n\/sbin\/shutdown\u00a0 This will shut down the system.
\n\/sbin\/sulogin\u00a0 This is the single user mode login.
\n\/sbin\/telinit\u00a0 This is the init process control initialization.
\n\/usr\/bin\/last\u00a0 This shows who was in the system last.
\n\/usr\/bin\/lastb\u00a0 This is about the same as last.
\n\/usr\/bin\/mesg\u00a0 This is to toggle writeble mode on your tty.
\n\/usr\/bin\/utmpdump This dumps a file for utmp (this lacks documentation)
\n\/usr\/bin\/wall\u00a0 This sends a message to all ttys.<\/p>\n

And then the init needs the following extra files\/dirs and commands from
\nthe initscripts package:<\/p>\n

\/bin\/doexec\u00a0 This lets you run a program under another name.
\n\/bin\/ipcalc\u00a0 This lets you manipulate IP addresses.
\n\/bin\/usleep\u00a0 This sleeps for microseconds.
\n\/etc\/X11\/prefdm\u00a0 This is the display manager preferrence file for X.
\n\/etc\/adjtime\u00a0 This is the Kernel Clock Config file.
\n\/etc\/init.d\u00a0 BSD init compatibilety directory.
\n\/etc\/initlog.conf This is the initlog configuration file.
\n\/etc\/inittab\u00a0 This is the main init configuration file.
\n\/etc\/modules\u00a0 This is where the kernel loads modules from at boot.
\n\/etc\/ppp\/ip-down This is a script for dialup internet connections.
\n\/etc\/ppp\/ip-up\u00a0 This is a script for dialup internet connections.
\n\/etc\/profile.d\/inputrc.csh Shell Key bindings for csh and tcsh.
\n\/etc\/profile.d\/inputrc.sh Shell Key bindings for sh and bash.
\n\/etc\/profile.d\/lang.csh\u00a0 Language files – i18n stuff for csh and tcsh.
\n\/etc\/profile.d\/lang.sh\u00a0 Language files – i18n stuff for sh and bash.
\n\/etc\/profile.d\/tmpdir.csh Set temporary directory for csh and tcsh.
\n\/etc\/profile.d\/tmpdir.sh Set temporary directory for sh and bash.
\n\/etc\/rc.d\/init.d\/functions Functions for scripts in init.d
\n\/etc\/rc.d\/init.d\/halt\u00a0 Runlevel 0 (shutdown\/halt) script.
\n\/etc\/rc.d\/init.d\/kheader Script to regenerate the \/boot\/kernel.h file.
\n\/etc\/rc.d\/init.d\/killall Script to make sure everything is shut off.
\n\/etc\/rc.d\/init.d\/mandrake_everytime Mandrake specific stuff.
\n\/etc\/rc.d\/init.d\/mandrake_firstime Mandrake post install stuff.
\n\/etc\/rc.d\/init.d\/netfs\u00a0 Mounts network filesystems.
\n\/etc\/rc.d\/init.d\/network Bring up\/down networking.
\n\/etc\/rc.d\/init.d\/random\u00a0 Script to help random number generation.
\n\/etc\/rc.d\/init.d\/rawdevices Device stuff for applications such as Oracle.
\n\/etc\/rc.d\/init.d\/single\u00a0 Single user script (runlevel 1)
\n\/etc\/rc.d\/init.d\/sound\u00a0 Launch sound.
\n\/etc\/rc.d\/init.d\/usb\u00a0 Launch USB support.
\n\/etc\/rc.d\/rc.local\u00a0 Boot time script, (like autoexec.bat in DOS).
\n\/etc\/rc.d\/rc.modules\u00a0 Bootup script for modules.
\n\/etc\/rc.d\/rc.sysinit\u00a0 Main system startup script.
\n\/etc\/rc.d\/rc0.d\/S00killall Runlevel 0 killall script link.
\n\/etc\/rc.d\/rc0.d\/S01halt\u00a0 Runlevel 0 halt script link.
\n\/etc\/rc.d\/rc1.d\/S00single Runlevel 1 single script link.
\n\/etc\/rc.d\/rc2.d\/S99local Runlevel 2 local script link. (rc.local)
\n\/etc\/rc.d\/rc3.d\/S99local Runlevel 3 local script link. (rc.local)
\n\/etc\/rc.d\/rc4.d\u00a0\u00a0 Runlevel 4 directory.
\n\/etc\/rc.d\/rc5.d\/S99local Runlevel 5 local script link. (rc.local)
\n\/etc\/rc.d\/rc6.d\/S00killall Runlevel 6 killall script link.
\n\/etc\/rc.d\/rc6.d\/S01reboot Runlevel 6 reboot script link.
\n\/etc\/rc.local\u00a0\u00a0 BSD init compatibilety file…. ?
\n\/etc\/rc.sysinit\u00a0\u00a0 BSD init compatibilety file…. ?
\n\/etc\/rc0.d\u00a0\u00a0 BSD init compatibilety directory.
\n\/etc\/rc1.d\u00a0\u00a0 BSD init compatibilety directory.
\n\/etc\/rc2.d\u00a0\u00a0 BSD init compatibilety directory.
\n\/etc\/rc3.d\u00a0\u00a0 BSD init compatibilety directory.
\n\/etc\/rc4.d\u00a0\u00a0 BSD init compatibilety directory.
\n\/etc\/rc5.d\u00a0\u00a0 BSD init compatibilety directory.
\n\/etc\/rc6.d\u00a0\u00a0 BSD init compatibilety directory.
\n\/etc\/sysconfig\/console\u00a0 Directory for console stuff, like the keymap.
\n\/etc\/sysconfig\/init\u00a0 Basic init boot configurations.
\n\/etc\/sysconfig\/network-scripts\/ifcfg-lo\u00a0 Network config for localhost.
\n\/etc\/sysconfig\/network-scripts\/ifdown\u00a0 Turning off interfaces script.
\n\/etc\/sysconfig\/network-scripts\/ifdown-post Post stuff for ifdown.
\n\/etc\/sysconfig\/network-scripts\/ifdown-ppp Turning off ppp.
\n\/etc\/sysconfig\/network-scripts\/ifdown-sl Turning off SLIP.
\n\/etc\/sysconfig\/network-scripts\/ifup\u00a0 Turning on interfaces script.
\n\/etc\/sysconfig\/network-scripts\/ifup-aliases Turning on alias interfaces.
\n\/etc\/sysconfig\/network-scripts\/ifup-ipx\u00a0 Turning on IPX.
\n\/etc\/sysconfig\/network-scripts\/ifup-plip Turning on PLIP.
\n\/etc\/sysconfig\/network-scripts\/ifup-post Post stuff for ifup.
\n\/etc\/sysconfig\/network-scripts\/ifup-ppp\u00a0 Turning on ppp.
\n\/etc\/sysconfig\/network-scripts\/ifup-routes Turning on routes.
\n\/etc\/sysconfig\/network-scripts\/ifup-sl\u00a0 Turning on SLIP.
\n\/etc\/sysconfig\/network-scripts\/network-functions\u00a0\u00a0\u00a0\u00a0 Functions for the scripts.
\n\/etc\/sysconfig\/rawdevices Raw device bindings.
\n\/etc\/sysctl.conf\u00a0 System Control configurations.
\n\/sbin\/consoletype\u00a0 This prints the console type.
\n\/sbin\/getkey\u00a0\u00a0 Prints the key strokes….
\n\/sbin\/ifdown\u00a0\u00a0 Application for the previous config files.
\n\/sbin\/ifup\u00a0\u00a0 Application for the previous config files.
\n\/sbin\/initlog\u00a0\u00a0 Logs msgs and events to the system logger.
\n\/sbin\/installkernel\u00a0 Installs a kernel (not for manual use).
\n\/sbin\/minilogd\u00a0\u00a0 * Totally lacking documentation.
\n\/sbin\/netreport\u00a0\u00a0 Reports changes of the network interface.
\n\/sbin\/ppp-watch\u00a0\u00a0 Application used by ifup-ppp.
\n\/sbin\/service\u00a0\u00a0 Can send commands to all services etc.
\n\/sbin\/setsysfont\u00a0 Sets the system font.
\n\/usr\/bin\/listhome\u00a0 Lists the users home directorys.
\n\/usr\/sbin\/detectloader\u00a0 Detect the current boot loader.
\n\/usr\/sbin\/supermount\u00a0 Automatic mount\/umount application.
\n\/usr\/sbin\/sys-unconfig\u00a0 System reconfiguration tool.
\n\/usr\/sbin\/usernetctl\u00a0 User Network interface control application.
\n\/var\/log\/wtmp\u00a0\u00a0 Previously logged in users entrys.
\n\/var\/run\/netreport\u00a0 Directory for the netreport application.
\n\/var\/run\/utmp\u00a0\u00a0 Currently logged in users entrys.<\/p>\n

So what do you really need to know of all that ?<\/p>\n

Well, here’s the simple basics of how it works and what you need to remember.<\/p>\n

The \/etc\/inittab is already explained.<\/p>\n

——————————————————————————-<\/p>\n

Here is how the runlevels works:<\/p>\n

The Runlevel can be one of 1 to 6 and the number means this:<\/p>\n

0 – halt
\n1 – Single user mode
\n2 – Multiuser, without NFS
\n3 – Full multiuser mode
\n4 – Unused
\n5 – X11
\n6 – reboot<\/p>\n

You change the runlevel with the `init` command, so say that you are
\nint runlevel 3 and you wanna go to single user mode for some reason,
\nthen you can do: init 1
\nIn a single user mode you can only be one user, root.
\nAnd in a single user enviorment you can’t do networking and
\nother tasks, the runlevel 1 is meant to be there for system maintenence.<\/p>\n

The two mostly used runlevels as default is 3 and 5.
\nMandrake and RedHat etc. uses Runlevel 5 as default, and so they
\nstart up with a GUI in X Windows.<\/p>\n

Typing init 0 will shut down the system, and typing runlevel 6 will
\nreboot the system.<\/p>\n

——————————————————————————-<\/p>\n

What determes what the various runlevels actually start at boot time
\nis what is in there respective directory:<\/p>\n

Runlevel 0: \/etc\/rc.d\/rc0.d\/
\nRunlevel 1: \/etc\/rc.d\/rc1.d\/
\nRunlevel 2: \/etc\/rc.d\/rc2.d\/
\nRunlevel 3: \/etc\/rc.d\/rc3.d\/
\nRunlevel 4: \/etc\/rc.d\/rc4.d\/
\nRunlevel 5: \/etc\/rc.d\/rc5.d\/
\nRunlevel 6: \/etc\/rc.d\/rc6.d\/<\/p>\n

——————————————————————————-<\/p>\n

So, here say that you wanna stop your web server from starting at boot time.
\nThe first thing you wanna do is to find out what runlevel you are in, that
\nyou do with the runlevel command like this:<\/p>\n

alien:~$ runlevel
\nN 3
\nalien:~$<\/p>\n

This means that you are in runlevel 3.
\nSo from here go to \/etc\/rc.d\/rc3.d\/ which is the directory for runlevel 3.<\/p>\n

alien:~$ cd \/etc\/rc.d\/rc3.d\/
\nalien: \/etc\/rc.d\/rc3.d\/ $<\/p>\n

Here you find the file that starts the webserver (this file is usually
\ncalled httpd with a character and a number infront of it (I’ll explain the
\ncharacter and the numbers soon), so list the contents of the current
\ndirectory and find it, or just do like this:<\/p>\n

alien: \/etc\/rc.d\/rc3.d\/ $ ls -l *httpd
\nlrwxrwxrwx\u00a0\u00a0\u00a0 1 root\u00a0\u00a0\u00a0\u00a0 root\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 15 Dec\u00a0 5 06:14 S85httpd -> ..\/init.d\/httpd
\nalien: \/etc\/rc.d\/rc3.d\/ $<\/p>\n

This says that S85httpd is a link to \/etc\/rc.d\/init.d\/httpd
\n(..\/init.d\/ if you’re standing in \/etc\/rc.d\/init.d\/ mean \/etc\/rc.d\/init.d\/)<\/p>\n

So just remove the link like this:<\/p>\n

alien: \/etc\/rc.d\/rc3.d\/ $ rm -f S85httpd
\nalien: \/etc\/rc.d\/rc3.d\/ $<\/p>\n

And that’s how you stop something from starting with the runlevel.<\/p>\n

——————————————————————————-<\/p>\n

Now, if you rather would have something more start with the runlevel
\nat boot time you do like this:<\/p>\n

You make a simple script that starts what you wanna have started and
\nput it in \/etc\/rc.d\/init.d\/.
\nSay that your scripts name is “mystart”, you are in runlevel 3 and you have
\nmade your script executable (chmod a+x mystart), and you have it
\nin your own home directory, then you do like this:<\/p>\n

alien: ~$ cp mystart \/etc\/rc.d\/init.d\/
\nalien: ~$ cd \/etc\/rc.d\/rc3.d
\nalien: \/etc\/rc.d\/rc3.d\/ $ ln -s ..\/init.d\/mystart Z00mystart
\nalien: \/etc\/rc.d\/rc3.d\/ $<\/p>\n

And that’s all of that.<\/p>\n

So now, what does the Z00 in Z00mystart or S85 in S85httpd mean ?
\nWell, as the system starts it will read file after file in it’s runlevels
\ndirectory in alphabetical order, so to get them to start in a preticular
\norder, the link names are made to determen that order.
\nSo the later in the alphabet the first character is the later it will boot,
\nand the same for for the number, the higher number the later it will start.<\/p>\n

So A00something will start before A01something
\nAnd Z99something will start later then X99something and so on.<\/p>\n

To get something to start at boot time you can also add it as a command
\nin the \/etc\/rc.d\/rc.local (or for some systems \/etc\/rc.local) file.
\nThat file is meant to be used for single commands and not to start up
\nmajor things like a server etc.<\/p>\n

Always try to load things with the actual runlevel which is the more correct
\nway, rather then adding them to the rc.local file<\/p>\n

——————————————————————————-<\/p>\n

So what’s the difference between the BSD init and the System V init ?
\nThe only thing that differs them that you need to rememer is that they
\nstore the startup scripts in different places.<\/p>\n

The startup scripts for the BSD init is mainly in the following places:<\/p>\n

\/etc\/rc0.d\/
\n\/etc\/rc1.d\/
\n\/etc\/rc2.d\/
\n\/etc\/rc3.d\/
\n\/etc\/rc4.d\/
\n\/etc\/rc5.d\/
\n\/etc\/rc6.d\/
\n\/etc\/rc.boot\/
\n\/etc\/rcS.d\/
\n\/etc\/init.d\/<\/p>\n

While the Syst V init stores its scripts mainly in:<\/p>\n

\/etc\/rc.d\/rc0.d\/
\n\/etc\/rc.d\/rc1.d\/
\n\/etc\/rc.d\/rc2.d\/
\n\/etc\/rc.d\/rc3.d\/
\n\/etc\/rc.d\/rc4.d\/
\n\/etc\/rc.d\/rc5.d\/
\n\/etc\/rc.d\/rc6.d\/
\n\/etc\/rc.d\/init.d\/<\/p>\n

In the BSD init the \/etc\/rc.boot\/ and the \/etc\/rcS.d\/ directorys
\nare more or less substitutes for the rc.local file since you can
\nput things in them that starts up at boot time…
\nwhat you put in \/etc\/rcS.d\/ will even start at single user mode,
\nso be careful what you put there.<\/p>\n

So basically, the actual scripts goes in the init.d directory
\nand you link them to the runlevel directory with a prefix to determen where
\nin the bootup they should be loaded.<\/p>\n

——————————————————————————-<\/p>\n

Here is an example of how an init script can be made.
\nHere I made a script that would start a daemon named “daemon”<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/sh
\n# example Example init script that would load ‘daemon’
\n#
\n# Version: @(#) \/etc\/rc.d\/inet.d\/example 0.01 19-Feb-2001
\n#
\n# Author: Billy (Alien), <alien@ktv.koping.se<\/a>>
\n#<\/p>\n

. \/etc\/rc.d\/init.d\/functions<\/p>\n

function status() {
\n\u00a0 ps aux | grep daemon &&
\n\u00a0 echo “Daemon is running.” ||
\n\u00a0 echo “Daemon is not running.”
\n}<\/p>\n

case “$1” in
\n\u00a0\u00a0\u00a0 start)
\n\u00a0\u00a0\u00a0 # Check if daemon is in our path.
\n\u00a0\u00a0\u00a0 if `which daemon` > \/dev\/null; then success || failure; fi
\n\u00a0\u00a0\u00a0 echo -n “Starting Daemon”
\n\u00a0daemon
\n\u00a0\u00a0\u00a0 echo
\n\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 stop)
\n\u00a0\u00a0\u00a0 # Check if daemon is in our path again.
\n\u00a0\u00a0\u00a0 if `which daemon` > \/dev\/null; then success || failure; fi
\n\u00a0\u00a0\u00a0 echo “Stopping Daemon”
\n\u00a0killall -15 daemon
\n\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 status)
\n\u00a0\u00a0\u00a0 echo “Status of Daemon:”
\n\u00a0status
\n\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 reload)
\n\u00a0\u00a0\u00a0 echo “Restarting Daemon.”
\n\u00a0killall -1 daemon
\n\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 restart)
\n\u00a0\u00a0\u00a0 if `which echo` > \/dev\/null; then success || failure; fi
\n\u00a0\u00a0\u00a0 $0 stop
\n\u00a0\u00a0\u00a0 $0 start
\n\u00a0\u00a0 ;;
\n\u00a0\u00a0\u00a0 *)
\n\u00a0\u00a0\u00a0 echo “Usage: $0 start|stop|restart|status”
\n\u00a0\u00a0\u00a0 exit 0
\nesac<\/p>\n

——————————————————————————-<\/p>\n

A note is that the success and failure functions\/commands come from
\nthe \/etc\/rc.d\/init.d\/functions file, which may not be present in all
\ndistributions of Linux, since it as far as I know only comes with
\nRedHat and Mandrake.<\/p>\n

——————————————————————————-<\/p>\n

The inits main configuration file is the \/etc\/inittab file, here is where
\nyou set which runlevel you you wanna have, and how many consoles you want
\netc, so here we go:<\/p>\n

The line where you actually set the runlevel looks like this (here runlevel 3):<\/p>\n

id:3:initdefault:<\/p>\n

Most RedHat like systems have runlevel 3 or 5 as default, but if you don’t
\nhave any networking, you may find it better to change to runlevel 2.<\/p>\n

Next in this file should be the system initialization.<\/p>\n

si::sysinit:\/etc\/rc.d\/rc.sysinit<\/p>\n

This line tells the system the path to the rc.sysinit where it loads
\nalot in the system, as system clock, sets the hostname, and
\nperforms a number of checks.<\/p>\n

Next in line is this:<\/p>\n

l0:0:wait:\/etc\/rc.d\/rc 0
\nl1:1:wait:\/etc\/rc.d\/rc 1
\nl2:2:wait:\/etc\/rc.d\/rc 2
\nl3:3:wait:\/etc\/rc.d\/rc 3
\nl4:4:wait:\/etc\/rc.d\/rc 4
\nl5:5:wait:\/etc\/rc.d\/rc 5
\nl6:6:wait:\/etc\/rc.d\/rc 6<\/p>\n

This tells the system where to load the programs and daemons it should load
\nfor the runlevel it’s in.
\nSay that we are in runlevel 3 (Default) then it looks at this line:<\/p>\n

l3:3:wait:\/etc\/rc.d\/rc 3<\/p>\n

And there after goes to load all what’s in \/etc\/rc.d\/rc3.d\/
\n(rc3.d or any rc?.d contains links to the real files or scripts
\nthat’s located in \/etc\/rc.d\/init.d, so if you wanna add something to
\nyour runlevel, just look how they have done it and do it in a similar fashion.
\nand make sure to not start any network dependent application before the
\nnetwork starts and so on…)<\/p>\n

Then it comes some other various stuff as trap the Ctrl+Alt+Del etc.<\/p>\n

After this comes the tty’s (Terminal Types), and there locations.<\/p>\n

1:2345:respawn:\/sbin\/mingetty tty1
\n2:2345:respawn:\/sbin\/mingetty tty2
\n3:2345:respawn:\/sbin\/mingetty tty3
\n4:2345:respawn:\/sbin\/mingetty tty4
\n5:2345:respawn:\/sbin\/mingetty tty5
\n6:2345:respawn:\/sbin\/mingetty tty6<\/p>\n

If you wanna add some more you can add like this:<\/p>\n

8:2345:respawn:\/sbin\/mingetty tty8
\n9:2345:respawn:\/sbin\/mingetty tty9
\n10:2345:respawn:\/sbin\/mingetty tty10
\n11:2345:respawn:\/sbin\/mingetty tty11<\/p>\n

And leav tty7 reserved for X-windows.<\/p>\n

Last in the file should only be some line about xdm and it’s location,
\nthis is if you have xdm installed…<\/p>\n

——————————————————————————-<\/p>\n

And if you have read the tutorial to this point you shouldent need any real
\nexplanation of this script.<\/p>\n

If you still dont understand how the init scripts work, read the
\nscripts in your system and try to understand them.
\nAnd also read this section about the init and the init scripts again.<\/p>\n

===============================================================================
\n9 – Basic Linux\/UNIX commands and operations.
\n===============================================================================<\/p>\n

This section is about Linux and UNIX basic commands and operations, and some
\nother explanations and tricks, since this is not a command bible,
\nI’ll explain each command breafly, with alot of help from the
\nman pages and the –help argument (let’s all thank the maker for cut & paste).
\nThen again, I’ve seen files that have claimed to be UNIX command bibles
\nthat are even breafer and hold less commands… though most of the authors
\nof those seems to be totally uncapeble of handling a UNIX and cant even spell,
\none of the worst examples I’ve seen was something like this:
\n“The UNIX bible, in this phile is all the UNIX commandz j00 need”
\nAnd after that was a list of commands without arguments… needless to say
\nis also that 99% of all UNIX commands were missing.
\nAnyway, enough of me making fun of those people now, and on with the tutorial.
\n(Which isn’t a UNIX command bible, just a note)
\nI will refer to “*nix” here, and that means any sort of UNIX system,
\nLinux, BSD, Solaris, SunOS, Xenix and so on included.<\/p>\n

——————————————————————————<\/p>\n

Here are the basic *nix commands, with breaf explanations.<\/p>\n

——————————————————————————<\/p>\n

adduser
\n\u00a0Syntax: adduser [arguments] <user>
\n\u00a0And can be used with the following arguments:
\n\u00a0-u uid
\n\u00a0-g group
\n\u00a0-G group,…
\n\u00a0-d home directory
\n\u00a0-s shell
\n\u00a0-c comment
\n\u00a0-k template
\n\u00a0-f inactive
\n\u00a0-e expire mm\/dd\/yy
\n\u00a0-p passwd
\n\u00a0Then there are a few arguments with no explanation:
\n\u00a0-o, -m, -n, and -r
\n\u00a0So say that you wanna add a user named “user” with password “resu”
\n\u00a0belonging to the group root with \/ as home directory using \/bin\/tcsh
\n\u00a0as shell, that would look as this:<\/p>\n

\u00a0adduser -p resu -g root -d \/ -s \/bin\/tcsh user<\/p>\n

——————————————————————————<\/p>\n

alias
\n\u00a0The alias command set’s an alias, as this: alias du=’du -h’
\n\u00a0This means that whenever you type: du
\n\u00a0it will really do: du -h<\/p>\n

\u00a0Typing alias by it self will display all set aliases.<\/p>\n

\u00a0For more information on the alias command do: help alias<\/p>\n

——————————————————————————<\/p>\n

apropos
\n\u00a0apropos checks for strings in the whatis database. say that you
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 are looking for a manual page about the `shutdown` command.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Then you can do: apropos shutdown
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 for more information, do: man whatis
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Or: man apropos<\/p>\n

——————————————————————————<\/p>\n

awk
\n\u00a0awk is a text formatting tool, that is HUGE, it’s actually a whole
\n\u00a0language, some say it’s not totally wrong to say that awk is not
\n\u00a0far off from a scripting version of C.
\n\u00a0However I wouldent go as far as to say that there resemblance
\n\u00a0is that great.
\n\u00a0awk’s most common use is about the same as ‘cut’, and it works like
\n\u00a0this: awk [argument-1] [argument-2] ….
\n\u00a0Here’s some example’s of converting an URL:<\/p>\n

\u00a0echo “http:\/\/www.bogus.com\/one\/two.htm<\/a>” | awk -F’\/’ ‘{print $3}’
\n\u00a0This will return: www.bogus.com<\/a>
\n\u00a0The -F will set a delimiter, and the ‘{print $3}’ will print the
\n\u00a0third feild, separated by the delimiter, which is www.bogus.com<\/a>,
\n\u00a0because there is 2 slashes, which makes the second slash the second
\n\u00a0feild, and so www.bogus.com<\/a> is the third feild.
\n\u00a0Here’s another example:<\/p>\n

\u00a0echo “http:\/\/www.bogus.com\/one\/two.htm<\/a>” | awk -F’\/’ ‘{print $(NF)}’
\n\u00a0This will return: two.htm
\n\u00a0The -F set’s the delimiter, which once again is \/, but this time
\n\u00a0we have used $NF which always resembles the last feild.
\n\u00a0Another example with NF is this:<\/p>\n

\u00a0echo “http:\/\/www.bogus.com\/one\/two.htm<\/a>” | awk -F’\/’ ‘{print $(NF – 1)}’
\n\u00a0This will return: one
\n\u00a0Because $(NF – 1) means the last feild minus one feild, which always
\n\u00a0will be the next last feild.<\/p>\n

\u00a0You only have to use the ()’s around variables when you do something
\n\u00a0with them like here “$(NF – 1)”, but you can use $(var) all the time
\n\u00a0if you want.<\/p>\n

\u00a0Here’s another example:<\/p>\n

echo “http:\/\/www.bogus.com\/one\/two.htm<\/a>” | awk -F’\/’ ‘{print $3 “\/” $(NF – 1)}’<\/p>\n

\u00a0This will return: www.bogus.com\/one<\/a>
\n\u00a0It will first print out the third feild separated by \/’s, which is
\n\u00a0www.bogus.com<\/a>, then it will print a \/, and then it will print out
\n\u00a0the next last feild which is one.<\/p>\n

\u00a0Here is a very shoer final example of awk:<\/p>\n

echo “http:\/\/www.bogus.com\/one\/two.htm<\/a>” | awk ‘{ while\u00a0 ( $(1) ) print }’<\/p>\n

\u00a0This will return: “http:\/\/www.bogus.com\/one\/two.htm<\/a>” forever.
\n\u00a0The “while ( $(1) )” means that as long as there is first feild,
\n\u00a0it will print the line line.
\n\u00a0And since there will always be a first feild it will continue
\n\u00a0forever.
\n\u00a0while in awk works as this: while ( condition ) action<\/p>\n

\u00a0As I said, awk is huge and is actually a whole language, so
\n\u00a0to explain all of it it would need a tutorial of it’s own.
\n\u00a0So I will not go any deeper into awk here, but you can as always
\n\u00a0read it’s manual page which is quite large.<\/p>\n

\u00a0So, for more info do: man awk<\/p>\n

——————————————————————————<\/p>\n

basename
\n\u00a0basename will strip directory and suffix from filenames.
\n\u00a0This command only have the two following flags:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0It works like this:
\n\u00a0alien:~$ basename \/usr\/local\/bin\/BitchX -a
\n\u00a0BitchX
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 alien:~$ basename http:\/\/www.domain.com\/path\/to\/file.html<\/a>
\n\u00a0file.html
\n\u00a0alien:~$<\/p>\n

\u00a0For more info do: man basename<\/p>\n

——————————————————————————<\/p>\n

bc
\n\u00a0A precision calculator, can be used with the following arguments:
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -l\u00a0\u00a0\u00a0\u00a0 Define the standard math library.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -w\u00a0\u00a0\u00a0\u00a0 Give warnings for extensions to POSIX bc.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s\u00a0\u00a0\u00a0\u00a0 Process exactly the POSIX bc language.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -q\u00a0\u00a0\u00a0\u00a0 Do not print the normal GNU bc welcome.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0 Print the version number and copyright and quit.<\/p>\n

——————————————————————————-<\/p>\n

BitchX
\n\u00a0BitchX is usually not default on any system, but it’s the far
\n\u00a0msot advanced IRC client to *nix.
\n\u00a0BitchX started as a script to ircii (ircii is irc2 an extended
\n\u00a0irc protocol, also EPIC which is more bareboned then BitchX is
\n\u00a0made from ircii), until BitchX got hard coded to the protocol
\n\u00a0in C, by panasync I belive.<\/p>\n

\u00a0BitchX has alot of arguments but can be executed without any
\n\u00a0arguments.
\n\u00a0This is the synatx: BitchX [arguments] <nickname> <server list>
\n\u00a0And here are the arguments anyway:<\/p>\n

\u00a0-H <hostname> this is if you have a virtual host.
\n\u00a0-c <#channel> auto join a channel, use a \\ infront of the #
\n\u00a0-b\u00a0 load .bitchxrc or .ircrc after connecting to a server
\n\u00a0-p <port> connect on port (default is 6667)
\n\u00a0-f\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 your terminal uses flow controls (^S\/^Q),
\n\u00a0\u00a0 so BitchX shouldn’t
\n\u00a0-F\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 your terminal doesn’t use flow control (default)
\n\u00a0-d\u00a0 dumb terminal mode (no ncurses)
\n\u00a0-q\u00a0 dont load the rc file ~\/.ircrc
\n\u00a0-r <file>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 loads file as list of servers to connect to
\n\u00a0-n <nickname> set the nickname to use
\n\u00a0-a\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 adds default servers and command line servers
\n\u00a0\u00a0 to server list
\n\u00a0-x\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 runs BitchX in “debug” mode
\n\u00a0-Z\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 use NAT address when doing dcc
\n\u00a0-P\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 toggle check pid.nickname for running program
\n\u00a0-v\u00a0 show client version
\n\u00a0-B\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 fork BitchX and return you to shell. pid check on.
\n\u00a0-l <file>\u00a0\u00a0\u00a0\u00a0 loads <file> in place of your ~\/.ircrc
\n\u00a0-L <file>\u00a0\u00a0\u00a0\u00a0 loads <file> in place of your .ircrc and
\n\u00a0\u00a0 expands $ expandos<\/p>\n

\u00a0The most common way of starting BitchX is this, say that you want
\n\u00a0to have the nick ‘Bash’ on server irc.bogus.com, then you can do:<\/p>\n

\u00a0BitchX Bash irc.bogus.com<\/p>\n

\u00a0There is so much to say about BitchX that it would need a tutorial
\n\u00a0of it’s own, I’m currently writing a BitchX script, so maybe
\n\u00a0I’ll write a BitchX tutorial some time =)<\/p>\n

——————————————————————————-<\/p>\n

bzcat<\/p>\n

\u00a0bzcat will uncompress a .bz2 file ‘on the fly’ as it cat’s it.
\n\u00a0the actual file will remain compressed after bzcat has displayed
\n\u00a0the contents.
\n\u00a0bzcat has to my knowlidge only one switch, and that’s
\n\u00a0-s, that uses less memory.
\n\u00a0bzcat works like this:<\/p>\n

\u00a0bzcat file.bz2<\/p>\n

\u00a0This can be good if you wanna search something in a text file
\n\u00a0that has been bzip2’d.
\n\u00a0Examples:<\/p>\n

\u00a0bzcat file.bz2 | grep ‘text string’
\n\u00a0bzcat file.bz2 | wc -l<\/p>\n

——————————————————————————-<\/p>\n

bzip2<\/p>\n

\u00a0Compression tool, compresses harder then the standard gzip.
\n\u00a0bzip2 can be used with the following arguments:
\n\u00a0-h –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print this message
\n\u00a0-d –decompress\u00a0\u00a0\u00a0\u00a0 force decompression
\n\u00a0-z –compress\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 force compression
\n\u00a0-k –keep\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 keep (don’t delete) input files
\n\u00a0-f –force\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 overwrite existing output files
\n\u00a0-t –test\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 test compressed file integrity
\n\u00a0-c –stdout\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output to standard out
\n\u00a0-q –quiet\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 suppress noncritical error messages
\n\u00a0-v –verbose\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 be verbose (a 2nd -v gives more)
\n\u00a0-L –license\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display software version & license
\n\u00a0-V –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display software version & license
\n\u00a0-s –small\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 use less memory (at most 2500k)
\n\u00a0-1 .. -9\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 set block size to 100k .. 900k
\n\u00a0Normally used as: bzip2 -d file.bz2 (to decompress a file)
\n\u00a0or bzip2 -z file (to compress a file)<\/p>\n

——————————————————————————-<\/p>\n

cat
\n\u00a0cat followed by a filename will bring the contents of the file
\n\u00a0out to the screen (stdout), and can be used with the following
\n\u00a0arguments:
\n\u00a0-A, –show-all\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 equivalent to -vET
\n\u00a0-b, –number-nonblank\u00a0\u00a0\u00a0 number nonblank output lines
\n\u00a0-e\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 equivalent to -vE
\n\u00a0-E, –show-ends\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display $ at end of each line
\n\u00a0-n, –number\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 number all output lines
\n\u00a0-s, –squeeze-blank\u00a0\u00a0\u00a0\u00a0\u00a0 never more than one single blank line
\n\u00a0-t\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 equivalent to -vT
\n\u00a0-T, –show-tabs\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display TAB characters as ^I
\n\u00a0-u\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (ignored)
\n\u00a0-v, –show-nonprinting\u00a0\u00a0 use ^ and M- notation, except for LFD and TAB
\n\u00a0–help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

——————————————————————————-<\/p>\n

cc
\n\u00a0C compiler, can be used with ALOT of arguments, do a man cc to find
\n\u00a0out just how many, it’s normally used to compile a .c source file to an
\n\u00a0executable binary, like this:
\n\u00a0cc -o program program.c<\/p>\n

——————————————————————————-<\/p>\n

cd
\n\u00a0change directory, works as this:
\n\u00a0cd \/way\/to\/directory\/I_want_to\/be\/in\/<\/p>\n

\u00a0No further explanation needed.<\/p>\n

——————————————————————————-<\/p>\n

chattr
\n\u00a0This is a very powerful command with which you can change the
\n\u00a0attributes on an ext2 file system.
\n\u00a0This means that you can make a file impossible to remove
\n\u00a0for as long as the attributes are there.<\/p>\n

\u00a0The attributes that can be added or removed are the follwoing:<\/p>\n

\u00a0A Don’t update atime.
\n\u00a0S Synchronous updates.
\n\u00a0a Append only.
\n\u00a0c Compressed.
\n\u00a0i Immutable.
\n\u00a0d No dump.
\n\u00a0s Secure deletion.
\n\u00a0u Undeletable.<\/p>\n

\u00a0So here is an example:<\/p>\n

\u00a0chattr +iu \/etc\/passwd<\/p>\n

\u00a0This makes it impossible to remove the \/etc\/passwd file unless
\n\u00a0you first do:<\/p>\n

\u00a0chattr -iu \/etc\/passwd<\/p>\n

\u00a0This can also be good for the logs, esecially, with the a attribute.
\n\u00a0To see the attributes, use: lsattr<\/p>\n

\u00a0For more info do: man chattr<\/p>\n

——————————————————————————-<\/p>\n

chmod
\n\u00a0chmod is a very useful command, it changes the rights of any file.
\n\u00a0To understand this command you need to understand how the permission
\n\u00a0line works:<\/p>\n

\u00a0-rwxr-xr-x\u00a0\u00a0\u00a0 1 alien\u00a0\u00a0\u00a0 users\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 58 Feb\u00a0 7 13:19 file1
\n\u00a0-rw-r–r–\u00a0\u00a0\u00a0 1 alien\u00a0\u00a0\u00a0 users\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3.1k Feb\u00a0 3 15:47 file2<\/p>\n

\u00a0Let’s break the -rwxr-xr-x down into 4 sections:
\n\u00a0– rwx r-x r-x
\n\u00a0The first – you can not change, that tells what sort of file it is,
\n\u00a0as if it’s a special file, a directory or a normal file.
\n\u00a0The second rwx is the rights of the owner of the file.
\n\u00a0The third r-x is the rights the group of the file has.
\n\u00a0And the fourth r-x tells us what right others\/anyone else has.
\n\u00a0The rights can be:<\/p>\n

\u00a0r read rights.
\n\u00a0w write rights.
\n\u00a0x\u00a0 execute rights.
\n\u00a0s\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 suid (su id, execute with someome else’s uid, usually root)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 t\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 saves the programs text on the swap device
\n\u00a0X executes file only if it’s in a dir that has execute rights<\/p>\n

\u00a0Then we need to know in what of those 3 last fields to set those
\n\u00a0rights, they can be set to:<\/p>\n

\u00a0a all (changes the 3 fields syncroniously)
\n\u00a0u user
\n\u00a0g group
\n\u00a0o others\/anyone else<\/p>\n

\u00a0You can add or remove rights with the following arguments:<\/p>\n

\u00a0+ add a right
\n\u00a0– remove a right
\n\u00a0= absolute right<\/p>\n

\u00a0So say now that we have a file called file1, that looks like this:<\/p>\n

\u00a0-rwxr-xr-x\u00a0\u00a0\u00a0 1 alien\u00a0\u00a0\u00a0 users\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 58 Feb\u00a0 7 13:19 file1<\/p>\n

\u00a0And we wanna take away all execution rights.
\n\u00a0Then we can either do:
\n\u00a0chmod a-x file1
\n\u00a0or
\n\u00a0chmod ugo-x file1
\n\u00a0And if we wanna make a file executable to everyone in it’s group,
\n\u00a0in this case the group “users”, then we do:
\n\u00a0chmod g+x file1<\/p>\n

\u00a0The other way to do this, is to use octal numbers to set the
\n\u00a0rights in the permission line.
\n\u00a0This requires a bit more thinking if your not use to it, but here’s
\n\u00a0how it works:<\/p>\n

\u00a0First we break up the permission line into 3 sections again (not
\n\u00a0counting the leading – or d), and then we put numbers on each
\n\u00a0of the 3 fields in each of the 3 sections.<\/p>\n

\u00a0– rwx rwx rwx
\n\u00a0\u00a0 421 421 421<\/p>\n

\u00a0Now to change a line to say: -rwxrx-r-x
\n\u00a0You would:
\n\u00a0x and r in the last field, that would mean 1+4=5, then the same thing
\n\u00a0in the middle field, and last we have r, w and x in the first so then
\n\u00a0we count them all, 1+2+4=7.
\n\u00a0If we now line up our results of this little mathematic we get: 755
\n\u00a0And so to change a permission line to -rwxrx-r-x we do:<\/p>\n

\u00a0chmod 755 <file><\/p>\n

\u00a0Here’s how it looks:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Oct\u00a0\u00a0\u00a0\u00a0 Bin\u00a0\u00a0\u00a0 Rights<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0 —
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1\u00a0 –x
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 10\u00a0 -w-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 11\u00a0 -wx
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 4\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 100\u00a0 r–
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 5\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101\u00a0 r-x
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 110\u00a0 rw-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 7\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 111\u00a0 rwx<\/p>\n

\u00a0Then we have the suid stuff for this with octal counting, that you set
\n\u00a0before the normal rights, I’ll explain that in a bit, first here
\n\u00a0is the number codes for the special options as suid.<\/p>\n

\u00a07*** SUID (user & group and set’s file +t)
\n\u00a06*** SUID (user & group)
\n\u00a05*** SUID +t (saves the files text to the swap partition and SUID user)
\n\u00a04*** SUID (user)
\n\u00a03*** SUID (group and set’s file +t)
\n\u00a02*** SUID (group)
\n\u00a01*** +t (saves the files text to the swap partition)
\n\u00a00*** nothing<\/p>\n

\u00a0Here’s how it looks:<\/p>\n

\u00a0Oct Bin\u00a0\u00a0\u00a0 Rights
\n\u00a0– — rwx rwx rwx
\n\u00a00\u00a0\u00a0\u00a0\u00a0 0 — — —
\n\u00a01\u00a0\u00a0 1 — — –t
\n\u00a02\u00a0 10 — –s —
\n\u00a03\u00a0 11 — –s –t
\n\u00a04 100 –s — —
\n\u00a05 101 –s — –t
\n\u00a06 110 –s –s —
\n\u00a07 111 –s –s –t<\/p>\n

\u00a0So if you have a file that we can call ‘foo.sh’ and you wanna make
\n\u00a0so that only the user has write permissions to it, the user
\n\u00a0and group has read and execute permissions, and all others has no
\n\u00a0rights at all to it.<\/p>\n

\u00a0Then we would count: others, 0, group 5, user 7, and then to SUID
\n\u00a0the group we add a 2 in front of what we have, which means:<\/p>\n

\u00a0chmod 2750 foo.sh<\/p>\n

\u00a0This will make foo.sh’s permission line look like this:<\/p>\n

\u00a0-rwxr-s—<\/p>\n

\u00a0To do the exact same with characters, you do:<\/p>\n

\u00a0chmod u+rwx,go-rwx,g+s foo.sh<\/p>\n

\u00a0The most common premissions for files is<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Executeble:\u00a0\u00a0\u00a0\u00a0\u00a0 (755)\u00a0\u00a0 -rwxr-xr-x
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Non-Executeble:\u00a0 (644)\u00a0\u00a0 -rw-r–r–<\/p>\n

\u00a0The easyest way of setting these is by eather do:<\/p>\n

\u00a0chmod 755 file
\n\u00a0or
\n\u00a0chmod =rwxrxrx file<\/p>\n

\u00a0chmod 644 file
\n\u00a0or
\n\u00a0chmod =rwrr file<\/p>\n

\u00a0For more information, do: man chmod<\/p>\n

——————————————————————————-<\/p>\n

chown
\n\u00a0chown changes owner of a file, it can actually also change the group.
\n\u00a0it works like this:<\/p>\n

\u00a0chown user file<\/p>\n

\u00a0This would change the owner of the file to user, but note that
\n\u00a0you can not change to owner of a file to a user that’s owned
\n\u00a0by someone else, same thing is that you can not change another
\n\u00a0users files so that you own them.
\n\u00a0Basicly, you need to be root to for this command in most cases.
\n\u00a0If you wanna change both the user and the group of a file, you do
\n\u00a0like this:<\/p>\n

\u00a0chown user.group file<\/p>\n

\u00a0That would change the owner of the file to user and the group
\n\u00a0of the file to group.
\n\u00a0For more info on this do: man chown<\/p>\n

——————————————————————————-<\/p>\n

chroot
\n\u00a0runs a command or interactive shell with special root directory.
\n\u00a0It works like this:<\/p>\n

\u00a0chroot \/new\/root\/directory\/ command<\/p>\n

\u00a0This can be good for some programs or commands, that rather
\n\u00a0would have \/ as root directory then ~\/ etc.<\/p>\n

——————————————————————————-<\/p>\n

cmp
\n\u00a0compares 2 files for differences, it can be used with the
\n\u00a0following arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -l\u00a0\u00a0\u00a0 Print the byte number (decimal) and the differing byte
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 values (oc- tal) for each difference.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s\u00a0\u00a0\u00a0 Print nothing for differing files; return exit status only.<\/p>\n

\u00a0It works like this:<\/p>\n

\u00a0cmp file1 file2
\n\u00a0Or
\n\u00a0cmp -s file1 file2<\/p>\n

\u00a0Not a very big, but still useful command.<\/p>\n

——————————————————————————-<\/p>\n

cp
\n\u00a0copy, copy’s a file from one location to another, may also copy
\n\u00a0one filename to another, used as this:
\n\u00a0cp file \/some\/other\/dir\/
\n\u00a0or
\n\u00a0cp file file.old<\/p>\n

——————————————————————————-<\/p>\n

crontab
\n\u00a0Crontab has already been explained in this tutorial.<\/p>\n

——————————————————————————-<\/p>\n

cut
\n\u00a0cut is a very powerful command, that allows you to cut in texts,
\n\u00a0It works like this: cut [arguments] <file><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -b, –bytes=LIST
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output only these bytes<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c, –characters=LIST
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output only these characters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -d, –delimiter=DELIM
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 use DELIM instead of TAB for field delimiter<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f, –fields=LIST
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output only these fields<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -n
\n\u00a0 (ignored)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s, –only-delimited
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 do not print lines not containing delimiters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –output-delimiter=STRING
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 use STRING as the output delimiter<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the default is to use the input delimiter<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0 display the help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0One of the many ways to use it is like this, say that you have a file
\n\u00a0named “hostlist” that contains this:<\/p>\n

\u00a0beta.linux.com has address 216.200.201.197
\n\u00a0shiftq.linux.com has address 216.200.201.195
\n\u00a0irc.linux.com has address 216.200.201.199
\n\u00a0oreilly.linux.com has address 208.201.239.30
\n\u00a0srom.linux.com has address 204.94.189.33
\n\u00a0admin.linux.com has address 216.200.201.194<\/p>\n

\u00a0And you ONLY wanna list the IP’s from it, then you do this:<\/p>\n

\u00a0cut -d ‘ ‘ -f 4 testfile<\/p>\n

\u00a0That will output only the IP’s, first we set the delimiter to ‘ ‘
\n\u00a0which means a space, then we display the 4’th field separated by
\n\u00a0the delimiter, which here is the IP’s.<\/p>\n

\u00a0Or that you have a file (say named column.txt) that contains this:<\/p>\n

\u00a0something\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 if we have to
\n\u00a0or someone\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 cut and paste
\n\u00a0likes to write\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the columns.
\n\u00a0in columns, we\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 So what do
\n\u00a0don’t like that\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 we do about
\n\u00a0especially not\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 this ?<\/p>\n

\u00a0To cut out each column is done like this:<\/p>\n

\u00a0cut -c 1-14 column.txt
\n\u00a0cut -c 23-40 column.txt<\/p>\n

\u00a0This would fist cut the file lengthwise and display characters
\n\u00a01-14 and then the same thing again but characters 23-40.<\/p>\n

\u00a0Now a simple way to get them in a long row instead of columns
\n\u00a0in a file is this:<\/p>\n

\u00a0cut -c 1-14 column.txt > no-columns.txt
\n\u00a0cut -c 23-40 column.txt >> no-columns.txt<\/p>\n

——————————————————————————-<\/p>\n

date
\n\u00a0date alone returns the current date and time in the following format:<\/p>\n

\u00a0day month\u00a0 date hr:min:sec timezone year<\/p>\n

\u00a0But can be executed with the following arguments:<\/p>\n

\u00a0%%\u00a0\u00a0 a literal %
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 %a\u00a0\u00a0 locale’s abbreviated weekday name (Sun..Sat)
\n\u00a0%A\u00a0\u00a0 locale’s full weekday name, variable length (Sunday..Saturday)
\n\u00a0\u00a0 %b\u00a0\u00a0 locale’s abbreviated month name (Jan..Dec)
\n\u00a0\u00a0 %B\u00a0\u00a0 locale’s full month name, variable length (January..December)
\n\u00a0\u00a0 %c\u00a0\u00a0 locale’s date and time (Sat Nov 04 12:02:33 EST 1989)
\n\u00a0\u00a0 %d\u00a0\u00a0 day of month (01..31)
\n\u00a0\u00a0 %D\u00a0\u00a0 date (mm\/dd\/yy)
\n\u00a0\u00a0 %e\u00a0\u00a0 day of month, blank padded ( 1..31)
\n\u00a0\u00a0 %h\u00a0\u00a0 same as %b
\n\u00a0\u00a0 %H\u00a0\u00a0 hour (00..23)
\n\u00a0\u00a0 %I\u00a0\u00a0 hour (01..12)
\n\u00a0\u00a0 %j\u00a0\u00a0 day of year (001..366)
\n\u00a0\u00a0 %k\u00a0\u00a0 hour ( 0..23)
\n\u00a0\u00a0 %l\u00a0\u00a0 hour ( 1..12)
\n\u00a0\u00a0 %m\u00a0\u00a0 month (01..12)
\n\u00a0\u00a0 %M\u00a0\u00a0 minute (00..59)
\n\u00a0\u00a0 %n\u00a0\u00a0 a newline
\n\u00a0\u00a0 %p\u00a0\u00a0 locale’s AM or PM
\n\u00a0\u00a0 %r\u00a0\u00a0 time, 12-hour (hh:mm:ss [AP]M)
\n\u00a0\u00a0 %s\u00a0\u00a0 seconds since 00:00:00, Jan 1, 1970 (a GNU extension)
\n\u00a0\u00a0 %S\u00a0\u00a0 second (00..60)
\n\u00a0\u00a0 %t\u00a0\u00a0 a horizontal tab
\n\u00a0\u00a0 %T\u00a0\u00a0 time, 24-hour (hh:mm:ss)
\n\u00a0\u00a0 %U\u00a0\u00a0 week number of year with Sunday as first day of week (00..53)
\n\u00a0\u00a0 %V\u00a0\u00a0 week number of year with Monday as first day of week (01..52)
\n\u00a0\u00a0 %w\u00a0\u00a0 day of week (0..6);\u00a0 0 represents Sunday
\n\u00a0\u00a0 %W\u00a0\u00a0 week number of year with Monday as first day of week (00..53)
\n\u00a0\u00a0 %x\u00a0\u00a0 locale’s date representation (mm\/dd\/yy)
\n\u00a0\u00a0 %X\u00a0\u00a0 locale’s time representation (%H:%M:%S)
\n\u00a0\u00a0 %y\u00a0\u00a0 last two digits of year (00..99)
\n\u00a0\u00a0 %Y\u00a0\u00a0 year (1970…)
\n\u00a0\u00a0 %z\u00a0\u00a0 RFC-822 style numeric timezone (-0500) (a nonstandard extension)
\n\u00a0\u00a0 %Z\u00a0\u00a0 time zone (e.g., EDT), or nothing if no time zone is determinable<\/p>\n

\u00a0For example, if you want to the time as hr:min:sec day, you would do:<\/p>\n

\u00a0date +’%H:%M:%S %a’<\/p>\n

\u00a0Or if you wanted to display the name of the month only, you would do:<\/p>\n

\u00a0date +%B<\/p>\n

——————————————————————————-<\/p>\n

dc
\n\u00a0dc is an arbitrary precision calculator.
\n\u00a0man dc for more info.<\/p>\n

——————————————————————————-<\/p>\n

dd
\n\u00a0disk duplicator, this is a very powerful command, that is
\n\u00a0useful for doing backups as well as creating boot floppy’s
\n\u00a0from images.
\n\u00a0Say now that you have a Slackware standard boot floppy image (bare.i)
\n\u00a0and you want to write it to a floppy, then you do this:<\/p>\n

\u00a0dd if=bare.i of=\/dev\/fd0 conv=sync<\/p>\n

\u00a0If you instead have a RedHat or Mandrake boot image, just replace
\n\u00a0the bare.i in the line with boot.img, under the condition that
\n\u00a0you are standing in a directory that contains that specific image.<\/p>\n

\u00a0The conv=sync part is just there to make sure that the disks are
\n\u00a0synced.<\/p>\n

\u00a0dd is a quite big command so I suggest you take a look at the man page.<\/p>\n

——————————————————————————-<\/p>\n

declare
\n\u00a0declare will declare a variable and may set attributes to it.
\n\u00a0The attributes declare can set or use with the following flags are:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -p\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 show variable with attributes.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -a\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to make a variable(s) an array (if supported)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to select from among function names only
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -F\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to display function names without definitions
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -r\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to make variable(s) readonly
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -x\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to export variable(s)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -i\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to make variable(s) have the `integer’ attribute set<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Using `+’ instead of `-‘ turns off the given attribute(s) instead
\n\u00a0of setting them.
\n\u00a0If declare is used within a function, the variables will be
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 local, the same way as if the `local` command had been used.<\/p>\n

\u00a0The -r option works the same as the `readonly` command.
\n\u00a0And the -r option can not be removed once it’s set.<\/p>\n

\u00a0Here’s a short example:<\/p>\n

\u00a0declare -xr foo=bar<\/p>\n

\u00a0This would do the same as to do:<\/p>\n

\u00a0export foo=bar; readonly foo<\/p>\n

\u00a0For more info on this, do: help declare<\/p>\n

——————————————————————————-<\/p>\n

depmod
\n\u00a0depmod loads kernel modules, and is a very powerful command,
\n\u00a0it’s greatest use is that it can reload all kernel modules
\n\u00a0in a single line:<\/p>\n

\u00a0depmod -a<\/p>\n

\u00a0This is especially good if you have recompiled some modules and
\n\u00a0installed them, and you don’t wanna reboot the system.
\n\u00a0The command also allows you to load single modules or several
\n\u00a0modules, like this:<\/p>\n

\u00a0depmod module1.o module2.o … etc.<\/p>\n

\u00a0For more info, man depmod<\/p>\n

——————————————————————————-<\/p>\n

df
\n\u00a0Reports filesystem disk space usage.
\n\u00a0df can be used with the following arguments:<\/p>\n

\u00a0-a, –all
\n\u00a0include filesystems having 0 blocks<\/p>\n

\u00a0–block-size=SIZE use SIZE-byte blocks<\/p>\n

\u00a0-h, –human-readable
\n\u00a0print sizes in human readable format (e.g., 1K 234M 2G)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -H, –si
\n\u00a0\u00a0\u00a0\u00a0 likewise, but use powers of 1000 not 1024<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -i, –inodes
\n\u00a0\u00a0\u00a0\u00a0\u00a0 list inode information instead of block usage<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -k, –kilobytes
\n\u00a0\u00a0\u00a0 like –block-size=1024<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -l, –local
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 limit listing to local filesystems<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -m, –megabytes
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 like –block-size=1048576<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –no-sync
\n\u00a0\u00a0 do\u00a0 not\u00a0 invoke\u00a0 sync\u00a0 before\u00a0 getting\u00a0 usage\u00a0 info (default)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -P, –portability
\n\u00a0 use the POSIX output format<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –sync invoke sync before getting usage info<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -t, –type=TYPE
\n\u00a0\u00a0 limit listing to filesystems of type TYPE<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -T, –print-type
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print filesystem type<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -x, –exclude-type=TYPE
\n\u00a0\u00a0\u00a0\u00a0 limit listing to filesystems not of type TYPE<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0 (ignored)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help display this help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0My favorite is to use: df -h<\/p>\n

——————————————————————————-<\/p>\n

dhcpcd
\n\u00a0dhcpcd is used to obtain an IP if you have dynamic IP on a LAN
\n\u00a0such as a cable modem with dynamic IP.<\/p>\n

——————————————————————————-<\/p>\n

dialog
\n\u00a0The dialog command has already been explained in this tutorial.<\/p>\n

——————————————————————————-<\/p>\n

diff
\n\u00a0diff is a very large command that finds the difference between
\n\u00a0two files, it’s very handy to have to make patches.
\n\u00a0The basic use of diff is as follows:
\n\u00a0diff file1 file2
\n\u00a0for more and full info on this command, do: man diff<\/p>\n

——————————————————————————-<\/p>\n

dir
\n\u00a0Same as “ls”.<\/p>\n

——————————————————————————-<\/p>\n

dmesg
\n\u00a0dmesg can print or control the kernel ring buffer.
\n\u00a0by default it’ll show a log of loaded and unloaded modules
\n\u00a0and other kernel events, like initialization if RAM disks etc.
\n\u00a0(this is flushed at each reboot)
\n\u00a0This is useful to make a boot.messages file, bu simply doing this:
\n\u00a0dmesg > boot.messages
\n\u00a0If there is any errors at the boot up this command is the first
\n\u00a0you would use to try to determen the error.<\/p>\n

\u00a0This is the syntax of dmesg (cut’n’paste of the man page):<\/p>\n

\u00a0dmesg [ -c ] [ -n level ] [ -s bufsize ]<\/p>\n

\u00a0The options (-c\/-n\/-s) means the following:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 clear the ring buffer contents after printing.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s bufsize
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 use\u00a0 a\u00a0 buffer\u00a0 of bufsize to query the kernel ring
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 buffer.\u00a0 This is 8196 by default (this matches\u00a0 the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 default\u00a0 kernel\u00a0 syslog\u00a0 buffer\u00a0 size in 2.0.33 and
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2.1.103).\u00a0 If you have set\u00a0 the\u00a0 kernel\u00a0 buffer\u00a0 to
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 larger\u00a0 than\u00a0 the\u00a0 default\u00a0 then this option can be
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 used to view the entire buffer.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -n level
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 set the level at which logging of messages is\u00a0 done
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to\u00a0 the\u00a0 console.\u00a0\u00a0 For\u00a0 example, -n 1 prevents all
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 messages, expect panic messages, from appearing\u00a0 on
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the\u00a0 console.\u00a0\u00a0 All\u00a0 levels\u00a0 of\u00a0 messages are still
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 written to \/proc\/kmsg, so syslogd(8) can\u00a0 still\u00a0 be
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 used\u00a0 to\u00a0 control\u00a0 exactly\u00a0 where\u00a0 kernel\u00a0 messages
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 appear.\u00a0 When the -n option is used, dmesg will not
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print or clear the kernel ring buffer.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 When both options are used, only the last option on
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the command line will have an effect.<\/p>\n

\u00a0An example of usage is this:<\/p>\n

\u00a0dmesg -c -s 16392<\/p>\n

\u00a0This would print the kernel ring buffer (with a buffer size of 16392)
\n\u00a0And then flush the contents.<\/p>\n

\u00a0For more info on this command do: man dmesg<\/p>\n

——————————————————————————-<\/p>\n

do
\n\u00a0do just does what it says, and is used in among others
\n\u00a0‘while’ loops, if you have read the whole tutorial this far
\n\u00a0(and have photographic memory) you understand what I’m saying.<\/p>\n

——————————————————————————-<\/p>\n

domainname
\n\u00a0See hostname.<\/p>\n

——————————————————————————-
\ndu
\n\u00a0du shows estimated file space usage.
\n\u00a0du is a good command to show how much space a directory takes up.
\n\u00a0I prefer to use it with the -h argument (human readable, see df).
\n\u00a0du has lots of arguments, do `man du` for a full list.<\/p>\n

——————————————————————————-<\/p>\n

echo
\n\u00a0echo will redisplay anything you put after it.
\n\u00a0This is perhaps the most used command in bash scripting, and
\n\u00a0very useful in everyday *nix handling as well, I’ll get back
\n\u00a0to that in a moment. but first, echo has the following arguments:<\/p>\n

\u00a0 -n\u00a0\u00a0\u00a0\u00a0 do not output the trailing newline<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -e\u00a0\u00a0\u00a0\u00a0 enable interpretation of the backslash-escaped characters
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 listed below<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -E\u00a0\u00a0\u00a0\u00a0 disable interpretation of those sequences in STRINGs<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help display this help and exit (should be alone)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output\u00a0 version\u00a0 information\u00a0 and\u00a0 exit\u00a0 (should be alone)<\/p>\n

\u00a0AND these:<\/p>\n

\u00a0e\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 backslash
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 suppress trailing newline
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 a\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 alert (BELL)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 f newline and vertical tab
\n\u00a0n new line
\n\u00a0r delete recursively (rest of line backwards)
\n\u00a0t vertical tab
\n\u00a0v newline and vertical tab (vertical tab ?)
\n\u00a0xa new line
\n\u00a0xb newline and vertical tab
\n\u00a0xc newline and vertical tab
\n\u00a0xd delete rest of line forward
\n\u00a0xe ascii … screws up the console (type reset to get it back)<\/p>\n

\u00a0So to get a bell (beep) you just do:<\/p>\n

\u00a0echo -e “\\a”<\/p>\n

\u00a0Or to screw up your console, do:<\/p>\n

\u00a0echo -e “\\xe”<\/p>\n

——————————————————————————-<\/p>\n

eject
\n\u00a0With eject you can eject removable medias, such as tapes, JAZ, ZIP,
\n\u00a0CD-rom and so on.
\n\u00a0The command is pretty self explanatory, and can be used with the
\n\u00a0following arguments:<\/p>\n

\u00a0-h\u00a0 –help
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0 –verbose
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -d\u00a0 –default
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -a\u00a0 –auto
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c\u00a0 –changerslot
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -t\u00a0 –trayclose
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -n\u00a0 –noop
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -r\u00a0 –cdrom
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s\u00a0 –scsi
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f\u00a0\u00a0 –floppy
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -q\u00a0 –tape<\/p>\n

\u00a0The eject command is used as follows: eject [argument] <name>
\n\u00a0The name is the name of th drive, either from \/dev, \/mnt or
\n\u00a0by it’s mountpoint name.<\/p>\n

——————————————————————————-<\/p>\n

else
\n\u00a0Used in ‘if’ statements, and does what it says, used like this:
\n\u00a0if [ “arg1” = “arg2” ]; then echo “match” ; else echo “no match” ; fi<\/p>\n

——————————————————————————-<\/p>\n

env
\n\u00a0Display the enviorment settings.
\n\u00a0Can be used with the following arguments:
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -i, –ignore-environment. start with an empty environment
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u, –unset=NAME. remove variable from the environment
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version<\/p>\n

——————————————————————————-<\/p>\n

exit
\n\u00a0exit is used to kill the current process.
\n\u00a0It can either be used to logout or to kill a running script from
\n\u00a0within the script, in the later case it can be used with a
\n\u00a0return number as argument, ie. exit 0<\/p>\n

——————————————————————————-<\/p>\n

expr
\n\u00a0expr is a counter or command line calculator, it can handle most
\n\u00a0simple integer calculations.
\n\u00a0It can use all the normal ways of counting including boolean
\n\u00a0operators, such as | OR, != NOT IS, and so on.
\n\u00a0It’s simply used as this: expr 1 + 1
\n\u00a0One thing to remember, since this is in the command line, if you use
\n\u00a0* (times), you have to use it like this: expr 2 ‘*’ 2
\n\u00a0The ‘ precise quote makes sure that the star is not treated
\n\u00a0as a wildcard.<\/p>\n

——————————————————————————-
\nfdisk
\n\u00a0fdisk is the classic disk handler, with fdisk you can edit your
\n\u00a0hard drive(s) in alot of ways, as adding or removing partitions,
\n\u00a0list the partitions and so on.
\n\u00a0You start fdisk as this: fdisk \/dev\/<disk to veiw\/edit>
\n\u00a0This may be a disk such as \/dev\/hda \/dev\/hdb \/dev\/hdc and so on.
\n\u00a0Note that you can not determen a specific HD partition to
\n\u00a0start from, since fdisk operates on the whole HD.<\/p>\n

\u00a0When you start fdisk you will have the following commands,
\n\u00a0followed by there explanation:<\/p>\n

\u00a0\u00a0\u00a0 a\u00a0\u00a0 toggle a bootable flag
\n\u00a0\u00a0\u00a0 b\u00a0\u00a0 edit bsd disklabel
\n\u00a0\u00a0\u00a0 c\u00a0\u00a0 toggle the dos compatibility flag
\n\u00a0\u00a0\u00a0 d\u00a0\u00a0 delete a partition
\n\u00a0\u00a0\u00a0 l\u00a0\u00a0 list known partition types
\n\u00a0\u00a0\u00a0 m\u00a0\u00a0 print this menu
\n\u00a0\u00a0\u00a0 n\u00a0\u00a0 add a new partition
\n\u00a0\u00a0\u00a0 o\u00a0\u00a0 create a new empty DOS partition table
\n\u00a0\u00a0\u00a0 p\u00a0\u00a0 print the partition table
\n\u00a0\u00a0\u00a0 q\u00a0\u00a0 quit without saving changes
\n\u00a0\u00a0\u00a0 s\u00a0\u00a0 create a new empty Sun disklabel
\n\u00a0\u00a0\u00a0 t\u00a0\u00a0 change a partitions system id
\n\u00a0\u00a0\u00a0 u\u00a0\u00a0 change display\/entry units
\n\u00a0\u00a0\u00a0 v\u00a0\u00a0 verify the partition table
\n\u00a0\u00a0\u00a0 w\u00a0\u00a0 write table to disk and exit
\n\u00a0\u00a0\u00a0 x\u00a0\u00a0 extra functionality (experts only)<\/p>\n

\u00a0And in ‘x’ the extra functionality (experts only) mode.<\/p>\n

\u00a0\u00a0\u00a0 b\u00a0\u00a0 move beginning of data in a partition
\n\u00a0\u00a0\u00a0 c\u00a0\u00a0 change number of cylinders
\n\u00a0\u00a0\u00a0 d\u00a0\u00a0 print the raw data in the partition table
\n\u00a0\u00a0\u00a0 e\u00a0\u00a0 list extended partitions
\n\u00a0\u00a0\u00a0 g\u00a0\u00a0 create an IRIX partition table
\n\u00a0\u00a0\u00a0 h\u00a0\u00a0 change number of heads
\n\u00a0\u00a0\u00a0 m\u00a0\u00a0 print this menu
\n\u00a0\u00a0\u00a0 p\u00a0\u00a0 print the partition table
\n\u00a0\u00a0\u00a0 q\u00a0\u00a0 quit without saving changes
\n\u00a0\u00a0\u00a0 r\u00a0\u00a0 return to main menu
\n\u00a0\u00a0\u00a0 s\u00a0\u00a0 change number of sectors\/track
\n\u00a0\u00a0\u00a0 v\u00a0\u00a0 verify the partition table
\n\u00a0\u00a0\u00a0 w\u00a0\u00a0 write table to disk and exit<\/p>\n

\u00a0For more info on fdisk, do: man fdisk<\/p>\n

——————————————————————————-<\/p>\n

file
\n\u00a0The file command will tell you what type of file a file is.
\n\u00a0file basically works like this:
\n\u00a0file [ -bciknsvzL ] [ -f namefile ] [ -m magicfiles ] file
\n\u00a0The options are as follows:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -b\u00a0\u00a0\u00a0\u00a0\u00a0 Do not prepend filenames to\u00a0 output\u00a0 lines\u00a0 (briefmode).<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c\u00a0\u00a0\u00a0\u00a0\u00a0 Cause\u00a0 a\u00a0 checking\u00a0 printout of the parsed form of
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the magic file.\u00a0 This is usually used in\u00a0 conjunction
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 with\u00a0 -m\u00a0 to\u00a0 debug\u00a0 a new magic file before installing it.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f namefile
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Read the names of the files to\u00a0 be\u00a0 examined\u00a0 from
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 namefile\u00a0 (one per line) before the argument list.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Either namefile or at least one filename\u00a0 argument
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 must\u00a0 be\u00a0 present; to test the standard input, use
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 “-” as a filename argument.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -i\u00a0\u00a0\u00a0\u00a0\u00a0 Causes\u00a0 the\u00a0 file\u00a0 command\u00a0 to\u00a0 output\u00a0 mime\u00a0 type
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 strings\u00a0 rather\u00a0 than\u00a0 the\u00a0 more traditional human
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 readable\u00a0 ones.\u00a0 Thus\u00a0 it\u00a0 may\u00a0 say\u00a0 “text\/plain;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 charset=us-ascii”\u00a0 rather than “ASCII text”. In
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 order for this option to work,\u00a0 file\u00a0 changes\u00a0 the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 way\u00a0 it\u00a0 handles\u00a0 files\u00a0 recognised by the command
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 it’s self (such as many of the\u00a0 text\u00a0 file\u00a0 types,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 directories\u00a0 etc), and makes use of an alternative
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 “magic” file.\u00a0 (See “FILES” section, below).<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -k\u00a0\u00a0\u00a0\u00a0\u00a0 Don’t stop at the first match, keep going.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -m list
\n\u00a0 Specify an\u00a0 alternate\u00a0 list\u00a0 of\u00a0 files\u00a0 containing
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 magic\u00a0 numbers.\u00a0\u00a0 This\u00a0 can be a single file, or a
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 colon-separated list of files.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -n\u00a0\u00a0\u00a0\u00a0\u00a0 Force stdout to be flushed\u00a0 after\u00a0 check\u00a0 a\u00a0 file.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 This\u00a0 is\u00a0 only useful if checking a list of files.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 It is intended to be used by programs\u00a0 want\u00a0 filetype
\n\u00a0 output from a pipe.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0\u00a0 Print the version of the program and exit.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -z\u00a0\u00a0\u00a0\u00a0\u00a0 Try to look inside compressed files.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -L\u00a0\u00a0\u00a0\u00a0\u00a0 option\u00a0 causes\u00a0 symlinks\u00a0 to\u00a0 be\u00a0 followed, as the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 like-named option in ls(1).\u00a0 (on systems that support
\n\u00a0 symbolic links).<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s\u00a0\u00a0\u00a0\u00a0\u00a0 Normally, file only attempts to read and determine
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the type of argument files which\u00a0 stat(2)\u00a0 reports
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 are\u00a0\u00a0 ordinary\u00a0 files.\u00a0\u00a0 This\u00a0 prevents\u00a0 problems,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 because reading special files\u00a0 may\u00a0 have\u00a0 peculiar
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 consequences.\u00a0\u00a0 Specifying\u00a0 the\u00a0 -s\u00a0 option causes
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 file to also read argument files which\u00a0 are\u00a0 block
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 or\u00a0 character\u00a0 special\u00a0 files.\u00a0 This is useful for
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 determining the filesystem types of\u00a0 the\u00a0 data\u00a0 in
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 raw\u00a0 disk\u00a0 partitions,\u00a0 which\u00a0 are\u00a0 block\u00a0 special
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 files.\u00a0 This option also causes file to\u00a0 disregard
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the file size as reported by stat(2) since on some
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 systems it reports a zero size for raw disk partitions.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Here’s a very simple usage example:
\n\u00a0file \/bin\/sh
\n\u00a0file script.sh<\/p>\n

\u00a0For more info do: man file<\/p>\n

——————————————————————————-<\/p>\n

find
\n\u00a0find is a very powerful and useful command, it is as good for finding
\n\u00a0a file name as to helping you secure your system against hackers.<\/p>\n

\u00a0find works basicly like this: find <path> [argument] <file><\/p>\n

\u00a0You REALLY need to read it’s manual page, if you wanna know
\n\u00a0about this command, but here are some examples:<\/p>\n

\u00a0Find all files that are set suid root:
\n\u00a0find \/ -perm +4000<\/p>\n

\u00a0Find all regular files named core (this will skip directory’s):
\n\u00a0find \/ -type f -name core<\/p>\n

\u00a0Find all filenames that contains the word ‘conf’:
\n\u00a0find \/ -name *conf*<\/p>\n

\u00a0Find all directory’s that ends with ‘bin’:
\n\u00a0find \/ -type d -name *bin<\/p>\n

\u00a0Find all files named test.sh and execute them:
\n\u00a0find \/ -name test.sh -exec {} \\;<\/p>\n

\u00a0Find all regular files that contains the word .exe and
\n\u00a0remove them by force without asking:
\n\u00a0find \/ -type f -name *.exe -exec rm {} -rf \\;<\/p>\n

\u00a0Even if you are root you may come across errors like this:<\/p>\n

\u00a0find: \/proc\/10502\/fd: Permission denied<\/p>\n

\u00a0The easiest way to deal with this is to add a: 2>\/dev\/null
\n\u00a0after your command string, that will direct all such errors
\n\u00a0to \/dev\/null (the black hole of UNIX :P)<\/p>\n

——————————————————————————-<\/p>\n

ftpwho
\n\u00a0ftpwho is a command where you can see how many users there are
\n\u00a0logged on to your ftp, under the condition that you have an
\n\u00a0ftp server on your system that is.<\/p>\n

——————————————————————————-<\/p>\n

g++
\n\u00a0GNU C++ compiler.
\n\u00a0See it’s man page.
\n——————————————————————————-<\/p>\n

gcc
\n\u00a0GNU C Compiler.
\n\u00a0See cc
\n\u00a0And see the gcc man page<\/p>\n

——————————————————————————-<\/p>\n

gdb
\n\u00a0GNU Debugger, has ALOT of commands and arguments,
\n\u00a0see: man gdb.<\/p>\n

——————————————————————————-<\/p>\n

gpm
\n\u00a0gpm is the Linux mouse daemon, it’s unspareble when it comes to
\n\u00a0working an a console, cut & paste is a wonderful thing.
\n\u00a0gpm works basicly as this: gpm [options]
\n\u00a0The most common options would be as this:<\/p>\n

\u00a0gpm -m \/dev\/mouse -t ps2<\/p>\n

\u00a0This would start a PS\/2 mouse, under the conditions that the
\n\u00a0PS\/2 port (\/dev\/psaux) is linked to the mouse device (\/dev\/mouse).<\/p>\n

\u00a0You can use “gpm -m \/dev\/psaux -t ps2” just as well.
\n\u00a0Or if you have a serial mouse no COM1 you can start it like this:<\/p>\n

\u00a0gpm -m \/dev\/cua0 -t ms<\/p>\n

\u00a0The -m argument means, the mouse device, and the -t argument is
\n\u00a0the protocol it’s going to use.<\/p>\n

\u00a0For a list of all gpm’s arguments do: gpm -h
\n\u00a0And for a list of all the possible mouse protocols, do: gpm -t help<\/p>\n

\u00a0The basic console cut & paste functions for a 3 button mouser is:<\/p>\n

\u00a0Left button – hold and drag to highlight text (copy’s text to memory).<\/p>\n

\u00a0Middle button – pastes text that are in memory (see left button)<\/p>\n

\u00a0Right button – mark a starting point with a single left click and then
\n\u00a0mark an end point with the right button to highlight the whole section.<\/p>\n

\u00a0Once you get it to work, you may add the line to: \/etc\/rc.d\/rc.local<\/p>\n

——————————————————————————-<\/p>\n

grep
\n\u00a0grep is another of the very powerful commands<\/p>\n

——————————————————————————-<\/p>\n

halt
\n\u00a0This will halt (shutdown -h now) your system.<\/p>\n

——————————————————————————-<\/p>\n

hdparm
\n\u00a0hdparm is a powerful tool to control your hard drives.
\n\u00a0It works like this: hdparm <arguments> <hard drive>
\n\u00a0The arguments can be:<\/p>\n

\u00a0 -a\u00a0\u00a0 get\/set fs readahead
\n\u00a0 -A\u00a0\u00a0 set drive read-lookahead flag (0\/1)
\n\u00a0 -c\u00a0\u00a0 get\/set IDE 32-bit IO setting
\n\u00a0 -C\u00a0\u00a0 check IDE power mode status
\n\u00a0 -d\u00a0\u00a0 get\/set using_dma flag
\n\u00a0 -D\u00a0\u00a0 enable\/disable drive defect-mgmt
\n\u00a0 -E\u00a0\u00a0 set cd-rom drive speed
\n\u00a0 -f\u00a0\u00a0 flush buffer cache for device on exit
\n\u00a0 -g\u00a0\u00a0 display drive geometry
\n\u00a0 -h\u00a0\u00a0 display terse usage information
\n\u00a0 -i\u00a0\u00a0 display drive identification
\n\u00a0 -I\u00a0\u00a0 read drive identification directly from drive
\n\u00a0 -k\u00a0\u00a0 get\/set keep_settings_over_reset flag (0\/1)
\n\u00a0 -K\u00a0\u00a0 set drive keep_features_over_reset flag (0\/1)
\n\u00a0 -L\u00a0\u00a0 set drive doorlock (0\/1) (removable harddisks only)
\n\u00a0 -m\u00a0\u00a0 get\/set multiple sector count
\n\u00a0 -n\u00a0\u00a0 get\/set ignore-write-errors flag (0\/1)
\n\u00a0 -p\u00a0\u00a0 set PIO mode on IDE interface chipset (0,1,2,3,4,…)
\n\u00a0 -P\u00a0\u00a0 set drive prefetch count
\n\u00a0 -q\u00a0\u00a0 change next setting quietly
\n\u00a0 -r\u00a0\u00a0 get\/set readonly flag (DANGEROUS to set)
\n\u00a0 -R\u00a0\u00a0 register an IDE interface (DANGEROUS)
\n\u00a0 -S\u00a0\u00a0 set standby (spindown) timeout
\n\u00a0 -t\u00a0\u00a0 perform device read timings
\n\u00a0 -T\u00a0\u00a0 perform cache read timings
\n\u00a0 -u\u00a0\u00a0 get\/set unmaskirq flag (0\/1)
\n\u00a0 -U\u00a0\u00a0 un-register an IDE interface (DANGEROUS)
\n\u00a0 -v\u00a0\u00a0 default; same as -acdgkmnru (-gr for SCSI, -adgr for XT)
\n\u00a0 -V\u00a0\u00a0 display program version and exit immediately
\n\u00a0 -W\u00a0\u00a0 set drive write-caching flag (0\/1) (DANGEROUS)
\n\u00a0 -X\u00a0\u00a0 set IDE xfer mode (DANGEROUS)
\n\u00a0 -y\u00a0\u00a0 put IDE drive in standby mode
\n\u00a0 -Y\u00a0\u00a0 put IDE drive to sleep
\n\u00a0 -Z\u00a0\u00a0 disable Seagate auto-powersaving mode<\/p>\n

\u00a0Some examples:
\n\u00a0hdparm -Tt \/dev\/hda (Time the cache\/device read times)
\n\u00a0hdparm -c 1 \/dev\/hda (This made my HD read the cache twice as fast)
\n\u00a0hdparm -Yy \/dev\/hda (This will totally power down the HD until
\n\u00a0\u00a0\u00a0 it’s needed, very useful to save power
\n\u00a0\u00a0\u00a0 or if you just need a minutes silence)<\/p>\n

\u00a0For more info: man hdparm<\/p>\n

——————————————————————————-<\/p>\n

head
\n\u00a0the head command by default brings up the 10 top lines of a file,
\n\u00a0but can be used with these arguments:<\/p>\n

\u00a0-<n>\u00a0\u00a0\u00a0 where the <n> is the number of lines to get
\n\u00a0\u00a0 -c, –bytes=SIZE\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print first SIZE bytes
\n\u00a0\u00a0 -n, –lines=NUMBER\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print first NUMBER lines instead of first 10
\n\u00a0\u00a0 -q, –quiet, –silent\u00a0\u00a0\u00a0 never print headers giving file names
\n\u00a0\u00a0 -v, –verbose\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 always print headers giving file names
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0Here’s some examples:<\/p>\n

\u00a0head file<\/p>\n

\u00a0head -1 file<\/p>\n

\u00a0head -50 file<\/p>\n

\u00a0head -c 100 file<\/p>\n

\u00a0This command can prove to be very useful.<\/p>\n

——————————————————————————-<\/p>\n

help
\n\u00a0help is a command that shows information on built in commands.
\n\u00a0like ., cd, jobs, %, test, etc.
\n\u00a0It works like this: help <command><\/p>\n

——————————————————————————-<\/p>\n

hexdump
\n\u00a0hexdump is a command that will give a hex dump of any file.
\n\u00a0For more info on this command do: man hexdump<\/p>\n

——————————————————————————-<\/p>\n

hexedit
\n\u00a0hexedit is a hex editor, very good for debugging binarys,
\n\u00a0hexedit has alot of internal commands, do: man hexedit
\n\u00a0for more help on it.<\/p>\n

——————————————————————————-<\/p>\n

hostname
\n\u00a0With no arguments it displays the current hostname.
\n\u00a0But can also set a new hostname, here are it’s arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0 -s, –short\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 short host name
\n\u00a0\u00a0\u00a0\u00a0 -a, –alias\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 alias names
\n\u00a0\u00a0\u00a0\u00a0 -i, –ip-address\u00a0\u00a0\u00a0\u00a0\u00a0 addresses for the hostname
\n\u00a0\u00a0\u00a0\u00a0 -f, –fqdn, –long\u00a0\u00a0\u00a0 long host name (FQDN)
\n\u00a0\u00a0\u00a0\u00a0 -d, –domain\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 DNS domain name
\n\u00a0\u00a0\u00a0\u00a0 -y, –yp, –nis\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NIS\/YP domainname
\n\u00a0\u00a0\u00a0\u00a0 -F, –file\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 read hostname or NIS domainname from given file<\/p>\n

\u00a0Here’s an example if you wanna change your hostname:<\/p>\n

\u00a0hostname -F \/etc\/HOSTNAME<\/p>\n

——————————————————————————-<\/p>\n

id
\n\u00a0Shows you a users ID, default your user UID, GID and group name.
\n\u00a0The command has some arguments it can be used with, like this:<\/p>\n

\u00a0id [argument] <user><\/p>\n

\u00a0Here are the arguments:<\/p>\n

\u00a0\u00a0 -a\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ignore, for compatibility with other versions
\n\u00a0\u00a0 -g, –group\u00a0\u00a0\u00a0\u00a0 print only the group ID
\n\u00a0\u00a0 -G, –groups\u00a0\u00a0\u00a0 print only the supplementary groups
\n\u00a0\u00a0 -n, –name\u00a0\u00a0\u00a0\u00a0\u00a0 print a name instead of a number, for -ugG
\n\u00a0\u00a0 -r, –real\u00a0\u00a0\u00a0\u00a0\u00a0 print the real ID instead of effective ID, for -ugG
\n\u00a0\u00a0 -u, –user\u00a0\u00a0\u00a0\u00a0\u00a0 print only the user ID
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0So `id -u` will return ‘0’ if you are root (same as `echo $UID`).<\/p>\n

——————————————————————————-<\/p>\n

ifdown
\n\u00a0ifdown is a command that will let you shutdown (deactivate) any
\n\u00a0ethernet device. I works as this: ifdown <device>
\n\u00a0So say that you have an eth0 running that you wanna shut down, then
\n\u00a0you just do this: ifdown eth0<\/p>\n

\u00a0For more info on how to set up an ethernet device,
\n\u00a0see section 7 (Networking) in this tutorial.<\/p>\n

——————————————————————————-<\/p>\n

ifup
\n\u00a0ifup works the same as ifdown, but activates the ethernet device
\n\u00a0rather then deactivate it.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 For more info on how to set up an ethernet device,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 see section 7 (Networking) in this tutorial.<\/p>\n

——————————————————————————-<\/p>\n

init
\n\u00a0init sets the runlevel for you.
\n\u00a0If you have read the whole of this tutorial to this point you know
\n\u00a0about where to look for what they mean.
\n\u00a0So if you do: init 0
\n\u00a0The system will shutdown and halt there.
\n\u00a0And if you type: init 6
\n\u00a0The system will reboot, etc.<\/p>\n

——————————————————————————-<\/p>\n

insmod
\n\u00a0insmod tries to installs a loadable module in the running kernel.
\n\u00a0It works like this:<\/p>\n

\u00a0insmod [arguments] <-o module_name> object_file [ sym-bol=value … ]<\/p>\n

\u00a0Here are the possible arguments:
\n\u00a0\u00a0 -f, –force\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Force loading under wrong kernel version
\n\u00a0\u00a0 -k, –autoclean\u00a0\u00a0\u00a0\u00a0 Make module autoclean-able
\n\u00a0\u00a0 -m\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Generate load map (so crashes can be traced)
\n\u00a0\u00a0 -o NAME
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –name=NAME\u00a0\u00a0\u00a0\u00a0 Set internal module name to NAME
\n\u00a0\u00a0 -p, –poll\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Poll mode; check if the module matches the kernel
\n\u00a0\u00a0 -s, –syslog\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Report errors via syslog
\n\u00a0\u00a0 -v, –verbose\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Verbose output
\n\u00a0\u00a0 -V, –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Show version
\n\u00a0\u00a0 -x\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Do not export externs
\n\u00a0\u00a0 -X\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Do export externs (default)<\/p>\n

\u00a0An example of how to use this is:<\/p>\n

\u00a0insmod -o 3c90x \/lib\/modules\/2.2.14\/net\/3c90x.o<\/p>\n

\u00a0This would load the 3c90x.o module with 3c90x as name.<\/p>\n

——————————————————————————-<\/p>\n

install
\n\u00a0install is a command that installs a file properly,
\n\u00a0it works like this: install [arguments] source destination
\n\u00a0The arguments can be any of the following:<\/p>\n

\u00a0 -b, –backup
\n\u00a0 make backup before removal<\/p>\n

\u00a0\u00a0 -c
\n\u00a0 (ignored)<\/p>\n

\u00a0-d, –directory
\n\u00a0 treat all arguments as directory names; create all
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 components of the specified directories<\/p>\n

\u00a0-D
\n\u00a0 create all leading components of DEST except the last,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 then copy SOURCE to DEST;\u00a0 useful in the 1st format<\/p>\n

\u00a0-g, –group=GROUP
\n\u00a0 set group ownership, instead of process’ current group<\/p>\n

\u00a0-m, –mode=MODE
\n\u00a0 set permission mode (as in chmod), instead of rwxr-xr-x<\/p>\n

\u00a0-o, –owner=OWNER
\n\u00a0 set ownership (super-user only)<\/p>\n

\u00a0-p, –preserve-timestamps
\n\u00a0 apply access\/modification times of SOURCE files to
\n\u00a0 corresponding destination files<\/p>\n

\u00a0-s, –strip
\n\u00a0 strip symbol tables, only for 1st and 2nd formats<\/p>\n

\u00a0-S, –suffix=SUFFIX
\n\u00a0 override the usual backup suffix<\/p>\n

\u00a0–verbose
\n\u00a0 print the name of each directory as it is created<\/p>\n

\u00a0-V, –version-control=WORD
\n\u00a0 override the usual version control<\/p>\n

\u00a0–help
\n\u00a0 display the help and exit<\/p>\n

\u00a0So if we have a file called foo and we want to install it in
\n\u00a0\/usr\/local\/bin\/, and we want it to have the following permission line:
\n\u00a0-rwxr-x—, then we want it to belong to the group ftp, then
\n\u00a0we do like this:<\/p>\n

\u00a0install -m 750 foo -g ftp \/usr\/local\/bin\/<\/p>\n

\u00a0We could also use:<\/p>\n

\u00a0install -m u+rwx,g+rx foo -g ftp \/usr\/local\/bin\/<\/p>\n

\u00a0Which would produce the same permission line.<\/p>\n

\u00a0The install command is good to use if you ever do anything that
\n\u00a0needs to be installed to the system, in a proper way.<\/p>\n

——————————————————————————-<\/p>\n

ipchains
\n\u00a0ipchains is a firewall\/wrapper that has ALOT of argument,
\n\u00a0it’s one of those huge commands, do: man ipchains
\n\u00a0for more information on this command.<\/p>\n

——————————————————————————-<\/p>\n

ispell
\n\u00a0Interactive Spell check, this is a useful little command,
\n\u00a0it’s basic usage is: ispell <file>
\n\u00a0It has the following commands:<\/p>\n

\u00a0R\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Replace the misspelled word completely.
\n\u00a0Space\u00a0\u00a0 Accept the word this time only.
\n\u00a0A\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Accept the word for the rest of this session.
\n\u00a0I\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Accept the word, and put it in your private dictionary.
\n\u00a0U\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Accept and add lowercase version to private dictionary.
\n\u00a00-n\u00a0\u00a0\u00a0\u00a0 Replace with one of the suggested words.
\n\u00a0L\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Look up words in system dictionary.
\n\u00a0X\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Write the rest of this file, ignoring misspellings,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 and start next file.
\n\u00a0Q\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Quit immediately.\u00a0 Asks for confirmation.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Leaves file unchanged.
\n\u00a0!\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Shell escape.
\n\u00a0^L\u00a0\u00a0\u00a0\u00a0\u00a0 Redraw screen.
\n\u00a0^Z\u00a0\u00a0\u00a0\u00a0\u00a0 Suspend program.
\n\u00a0?\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Show the help screen.<\/p>\n

\u00a0Just run it on a file and test it for your self.<\/p>\n

——————————————————————————-<\/p>\n

kill
\n\u00a0kill is a very powerful command that can (if you’re root)
\n\u00a0kill any running process no the system.
\n\u00a0it works as: kill -<signal> <PID><\/p>\n

\u00a0Pid is short for Process ID, which you get with the `ps` command.<\/p>\n

\u00a0The signals can be any of the following:<\/p>\n

\u00a0POSIX signals:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Signal\u00a0\u00a0\u00a0\u00a0 Value\u00a0\u00a0\u00a0\u00a0 Action\u00a0\u00a0 Comment
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ———————————————————————-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGHUP\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Hangup detected on controlling terminal
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 or death of controlling process
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGINT\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Interrupt from keyboard
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGQUIT\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Quit from keyboard
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGILL\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 4\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Illegal Instruction
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGABRT\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Abort signal from abort(3)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGFPE\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 8\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Floating point exception
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGKILL\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 9\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 AEF\u00a0\u00a0\u00a0 Kill signal
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGSEGV\u00a0\u00a0\u00a0\u00a0\u00a0 11\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Invalid memory reference
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGPIPE\u00a0\u00a0\u00a0\u00a0\u00a0 13\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Broken pipe: write to pipe with no readers
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGALRM\u00a0\u00a0\u00a0\u00a0\u00a0 14\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Timer signal from alarm(2)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGTERM\u00a0\u00a0\u00a0\u00a0\u00a0 15\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Termination signal
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGUSR1\u00a0\u00a0 30,10,16\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 User-defined signal 1
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGUSR2\u00a0\u00a0 31,12,17\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 User-defined signal 2
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGCHLD\u00a0\u00a0 20,17,18\u00a0\u00a0\u00a0\u00a0 B\u00a0\u00a0\u00a0\u00a0 Child stopped or terminated
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGCONT\u00a0\u00a0 19,18,25\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Continue if stopped
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGSTOP\u00a0\u00a0 17,19,23\u00a0\u00a0\u00a0 DEF\u00a0\u00a0\u00a0 Stop process
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGTSTP\u00a0\u00a0 18,20,24\u00a0\u00a0\u00a0\u00a0 D\u00a0\u00a0\u00a0\u00a0 Stop typed at tty
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGTTIN\u00a0\u00a0 21,21,26\u00a0\u00a0\u00a0\u00a0 D\u00a0\u00a0\u00a0\u00a0 tty input for background process
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGTTOU\u00a0\u00a0 22,22,27\u00a0\u00a0\u00a0\u00a0 D\u00a0\u00a0\u00a0\u00a0 tty output for background process<\/p>\n

\u00a0Non-POSIX signals:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Signal\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Value\u00a0\u00a0\u00a0\u00a0 Action\u00a0\u00a0 Comment
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ———————————————————————-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGBUS\u00a0\u00a0\u00a0\u00a0\u00a0 10,7,10\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Bus error (bad memory access)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGPOLL\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Pollable event (Sys V). Synonym of SIGIO
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGPROF\u00a0\u00a0\u00a0\u00a0 27,27,29\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Profiling timer expired
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGSYS\u00a0\u00a0\u00a0\u00a0\u00a0 12,-,12\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Bad argument to routine (SVID)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGTRAP\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 5\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 Trace\/breakpoint trap
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGURG\u00a0\u00a0\u00a0\u00a0\u00a0 16,23,21\u00a0\u00a0\u00a0\u00a0 B\u00a0\u00a0\u00a0\u00a0 Urgent condition on socket (4.2 BSD)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGVTALRM\u00a0\u00a0 26,26,28\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Virtual alarm clock (4.2 BSD)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGXCPU\u00a0\u00a0\u00a0\u00a0 24,24,30\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 CPU time limit exceeded (4.2 BSD)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGXFSZ\u00a0\u00a0\u00a0\u00a0 25,25,31\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 File size limit exceeded (4.2 BSD)<\/p>\n

\u00a0Other signals:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Signal\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Value\u00a0\u00a0\u00a0\u00a0 Action\u00a0\u00a0 Comment
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ——————————————————————-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGIOT\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C\u00a0\u00a0\u00a0\u00a0 IOT trap. A synonym for SIGABRT
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGEMT\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 7,-,7
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGSTKFLT\u00a0\u00a0\u00a0 -,16,-\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Stack fault on coprocessor
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGIO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 23,29,22\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 I\/O now possible (4.2 BSD)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGCLD\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -,-,18\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A synonym for SIGCHLD
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGPWR\u00a0\u00a0\u00a0\u00a0\u00a0 29,30,19\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Power failure (System V)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGINFO\u00a0\u00a0\u00a0\u00a0\u00a0 29,-,-\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A synonym for SIGPWR
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGLOST\u00a0\u00a0\u00a0\u00a0\u00a0 -,-,-\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 File lock lost
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGWINCH\u00a0\u00a0\u00a0 28,28,20\u00a0\u00a0\u00a0\u00a0 B\u00a0\u00a0\u00a0\u00a0 Window resize signal (4.3 BSD, Sun)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SIGUNUSED\u00a0\u00a0\u00a0 -,31,-\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0\u00a0\u00a0\u00a0 Unused signal (will be SIGSYS)<\/p>\n

\u00a0When you use the kill you can either use the numeric code, as
\n\u00a0say that we have a PID 1234 that we wanna kill, then we can either
\n\u00a0do: kill -9 1234 or we can do: kill -KILL 1234
\n\u00a0So you don’t have to include that leading SIG in the signals
\n\u00a0when you use them by name.<\/p>\n

——————————————————————————-<\/p>\n

killall
\n\u00a0killall is the same as kill but kills processes by name,
\n\u00a0As say that you have 10 processes running all named: httpd
\n\u00a0and you wanna kill them all in one command.
\n\u00a0Then: killall -9 httpd\u00a0 would be the way to go about it.<\/p>\n

——————————————————————————-<\/p>\n

lastlog
\n\u00a0lastlog is a command that shows you a list of the users and when
\n\u00a0they last logged in, from what host and on which port.
\n\u00a0lastlog can be used with the following arguments:<\/p>\n

\u00a0-u username
\n\u00a0-t number of days<\/p>\n

\u00a0so if I wanna check if a user named ‘user’ has logged in during
\n\u00a0the last 50 days I do: lastlog -u user -t 50<\/p>\n

——————————————————————————-<\/p>\n

ldconfig
\n\u00a0ldconfig updates the list of directory’s in where library’s can be
\n\u00a0found as \/lib and \/usr\/lib, if you wanna add a directory to this you
\n\u00a0can add them in \/etc\/ld.so.conf
\n\u00a0By just typing `ldconfig` you will update this, but it can
\n\u00a0also be executed with more arguments, for more info on this
\n\u00a0command do: man ldconfig<\/p>\n

\u00a0Just note that this is not really a command that you will use
\n\u00a0every day.<\/p>\n

——————————————————————————-<\/p>\n

ldd
\n\u00a0ldd can check what librarys a dynamicly executable file needs.
\n\u00a0and it can have the following switches:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print version information and exit
\n\u00a0\u00a0 -d, –data-relocs\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 process data relocations
\n\u00a0\u00a0 -r, –function-relocs\u00a0\u00a0 process data and function relocations
\n\u00a0\u00a0 -v, –verbose\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print all information<\/p>\n

\u00a0It works like this:<\/p>\n

\u00a0ldd <file><\/p>\n

\u00a0Example:<\/p>\n

\u00a0ldd \/sbin\/ifconfig<\/p>\n

——————————————————————————-<\/p>\n

less
\n\u00a0less is more then more ….. ummmm
\n\u00a0less works a bit like cat but it will stop at each screen and you
\n\u00a0can scroll up and down in the file to view it’s contents,
\n\u00a0it works basicly like this: less <textfile>
\n\u00a0Do a: less –help
\n\u00a0For a full index of it’s commands, and note that you get out
\n\u00a0of less by pressing the letter ‘q’.<\/p>\n

——————————————————————————-<\/p>\n

lilo
\n\u00a0lilo is the LInux LOader, and is on most distros the default
\n\u00a0boot loader, with lilo you can rewrite your boot sector and
\n\u00a0everything that involves your booting or switching between
\n\u00a0several installed operating systems, lilo’s configuration file
\n\u00a0is \/etc\/lilo.conf
\n\u00a0for more info about lilo and what lilo can do do: man lilo<\/p>\n

——————————————————————————-<\/p>\n

ln
\n\u00a0link, with ln you can link any file, this is essential to *nix
\n\u00a0as, say that you have a config file that needs to be in the same
\n\u00a0dir as it’s program but you want it in \/etc with all the other
\n\u00a0configuration files, then you can link it to \/etc so the link
\n\u00a0appears in \/etc and works just like the real file.<\/p>\n

\u00a0Usually ln is used to set symbolic links (sym links) where you
\n\u00a0can see the difference of the link and the file and you can remove
\n\u00a0the link without it affecting the real file.
\n\u00a0A symbolic link is set in this way: ln -s file link<\/p>\n

——————————————————————————-<\/p>\n

lndir
\n\u00a0link directory, about the same as ln but links directory’s,
\n\u00a0see the: man lndir<\/p>\n

——————————————————————————-<\/p>\n

loadkeys
\n\u00a0loadkeys, basicly works like: loadkeys \/usr\/lib\/kbd\/keymaps\/<keymap>
\n\u00a0but also has some arguments (that I never used), if you want
\n\u00a0more info: man loadkeys<\/p>\n

——————————————————————————-<\/p>\n

locate
\n\u00a0locate can locate any file that’s read into a database,
\n\u00a0you update this database if you as root type: updatedb
\n\u00a0locate works basicly like: locate <whatever-you-wanna-find>
\n\u00a0but can be executed with alot of arguments, do: locate –help
\n\u00a0or for more info: man locate<\/p>\n

——————————————————————————-<\/p>\n

logout
\n\u00a0logout does what it says, it logs you off the shell.<\/p>\n

——————————————————————————-<\/p>\n

lpq
\n\u00a0line printer que, checks if you have any printer jobs on que.<\/p>\n

——————————————————————————-<\/p>\n

lpr
\n\u00a0line printer, has alot of commands, but basicly works as: lpr <file>
\n\u00a0to print a file, the lpr command has alot of arguments,
\n\u00a0do: man lpr for more info.<\/p>\n

——————————————————————————-<\/p>\n

lprm
\n\u00a0line printer remove, removes any qued jobs (lpq) by there entry number.<\/p>\n

——————————————————————————-<\/p>\n

ls
\n\u00a0this is the most basic of all basic commands to know.
\n\u00a0ls lists the contents of a directory, if you type just `ls`
\n\u00a0it will list the contents of the current directory, but it can also
\n\u00a0be used as `ls \/way\/to\/some\/other\/dir\/` to list the contents of
\n\u00a0some other directory, ls has alot of arguments which are:<\/p>\n

\u00a0\u00a0 -a, –all
\n\u00a0 do not hide entries starting with .<\/p>\n

\u00a0\u00a0 -A, –almost-all
\n\u00a0 do not list implied . and ..<\/p>\n

\u00a0-b, –escape
\n\u00a0 print octal escapes for nongraphic characters<\/p>\n

\u00a0–block-size=SIZE
\n\u00a0 use SIZE-byte blocks<\/p>\n

\u00a0\u00a0 -B, –ignore-backups
\n\u00a0 do not list implied entries ending with ~<\/p>\n

\u00a0-c
\n\u00a0 sort by change time; with -l: show ctime<\/p>\n

\u00a0-C
\n\u00a0 list entries by columns<\/p>\n

\u00a0–color[=WHEN]
\n\u00a0 control whether color is used to distinguish file
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 types.\u00a0 WHEN may be `never’, `always’, or `auto’<\/p>\n

\u00a0-d, –directory
\n\u00a0 list directory entries instead of contents<\/p>\n

\u00a0-D, –dired
\n\u00a0 generate output designed for Emacs’ dired mode<\/p>\n

\u00a0 -f
\n\u00a0 do not sort, enable -aU, disable -lst<\/p>\n

\u00a0\u00a0 -F, –classify
\n\u00a0 append indicator (one of *\/=@|) to entries<\/p>\n

\u00a0\u00a0\u00a0\u00a0 –format=WORD
\n\u00a0 across -x, commas -m, horizontal -x, long -l,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 single-column -1, verbose -l, vertical -C<\/p>\n

\u00a0\u00a0\u00a0\u00a0 –full-time
\n\u00a0 list both full date and full time<\/p>\n

\u00a0-g
\n\u00a0 (ignored)<\/p>\n

\u00a0-G, –no-group
\n\u00a0 inhibit display of group information<\/p>\n

\u00a0-h, –human-readable
\n\u00a0 print sizes in human readable format (e.g., 1K 234M 2G)<\/p>\n

\u00a0-H, –si
\n\u00a0 likewise, but use powers of 1000 not 1024<\/p>\n

\u00a0\u00a0\u00a0\u00a0 –indicator-style=WORD
\n\u00a0 append indicator with style WORD to entry names:
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 none (default), classify (-F), file-type (-p)<\/p>\n

\u00a0-i, –inode
\n\u00a0 print index number of each file<\/p>\n

\u00a0-I, –ignore=PATTERN
\n\u00a0 do not list implied entries matching shell PATTERN<\/p>\n

\u00a0-k, –kilobytes
\n\u00a0 like –block-size=1024<\/p>\n

\u00a0-l
\n\u00a0 use a long listing format<\/p>\n

\u00a0-L, –dereference
\n\u00a0 list entries pointed to by symbolic links<\/p>\n

\u00a0-m
\n\u00a0 fill width with a comma separated list of entries<\/p>\n

\u00a0-n, –numeric-uid-gid
\n\u00a0 list numeric UIDs and GIDs instead of names<\/p>\n

\u00a0-N, –literal
\n\u00a0 print raw entry names (don’t treat e.g. control
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 characters specially)<\/p>\n

\u00a0-o
\n\u00a0 use long listing format without group info<\/p>\n

\u00a0-p, –file-type
\n\u00a0 append indicator (one of \/=@|) to entries<\/p>\n

\u00a0-q, –hide-control-chars
\n\u00a0 print ? instead of non graphic characters<\/p>\n

\u00a0\u00a0\u00a0\u00a0 –show-control-chars
\n\u00a0 show non graphic characters as-is (default)<\/p>\n

\u00a0-Q, –quote-name
\n\u00a0 enclose entry names in double quotes<\/p>\n

\u00a0\u00a0\u00a0\u00a0 –quoting-style=WORD
\n\u00a0 use quoting style WORD for entry names:
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 literal, shell, shell-always, c, escape<\/p>\n

\u00a0-r, –reverse
\n\u00a0 reverse order while sorting<\/p>\n

\u00a0-R, –recursive
\n\u00a0 list subdirectories recursively<\/p>\n

\u00a0-s, –size
\n\u00a0 print size of each file, in blocks<\/p>\n

\u00a0-S
\n\u00a0 sort by file size<\/p>\n

\u00a0\u00a0\u00a0\u00a0 –sort=WORD
\n\u00a0 extension -X, none -U, size -S, time -t, version -v
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 status -c, time -t, atime -u, access -u, use -u<\/p>\n

\u00a0\u00a0\u00a0 –time=WORD
\n\u00a0 show time as WORD instead of modification time:
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 atime, access, use, ctime or status; use
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 specified time as sort key if –sort=time<\/p>\n

\u00a0-t
\n\u00a0 sort by modification time<\/p>\n

\u00a0-T, –tabsize=COLS
\n\u00a0 assume tab stops at each COLS instead of 8<\/p>\n

\u00a0-u
\n\u00a0 sort by last access time; with -l: show atime<\/p>\n

\u00a0-U
\n\u00a0 do not sort; list entries in directory order<\/p>\n

\u00a0-v
\n\u00a0 sort by version<\/p>\n

\u00a0-w, –width=COLS
\n\u00a0 assume screen width instead of current value<\/p>\n

\u00a0-x
\n\u00a0 list entries by lines instead of by columns<\/p>\n

\u00a0-X
\n\u00a0 sort alphabetically by entry extension<\/p>\n

\u00a0-1
\n\u00a0 list one file per line<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0Some good examples are:<\/p>\n

\u00a0ls -la
\n\u00a0ls -laF
\n\u00a0ls -laF –color
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ls -d *\/<\/p>\n

\u00a0Also see earlier in this tutorial about the `alias` command<\/p>\n

——————————————————————————-<\/p>\n

lsattr
\n\u00a0list attributes, this command lists a files file system attributes.
\n\u00a0For more info see: man lsattr<\/p>\n

——————————————————————————-<\/p>\n

lsmod
\n\u00a0list modules, lists all loaded modules with a very brief information.<\/p>\n

——————————————————————————-<\/p>\n

lsof
\n\u00a0list open files, this is a huge command, so if you really
\n\u00a0wanna find out more about this interesting command you will have
\n\u00a0to read the manual page for it.
\n\u00a0But here’s an example of use for it:<\/p>\n

\u00a0lsof -p 1<\/p>\n

\u00a0Which would be the same as:<\/p>\n

\u00a0lsof -p `pidof init`<\/p>\n

\u00a0Here’s another example:<\/p>\n

\u00a0lsof -p `pidof httpd | sed ‘s\/\\ \/,\/g’`<\/p>\n

\u00a0The “-p” means that the following argument will be a PID (Process ID).
\n\u00a0The “sed” part in the later example replaces any spaces with “,” since
\n\u00a0lsof doesnt want spaces between the pids, as the output of pidof gives.<\/p>\n

\u00a0For more info see: man lsof<\/p>\n

——————————————————————————-<\/p>\n

lynx
\n\u00a0lynx is a console based world wide web browser, that has alot of
\n\u00a0arguments with which it can be executed, but it basicly works like
\n\u00a0this: lynx <url>
\n\u00a0If you press ‘g’ while in lynx you can type in the url where you
\n\u00a0wanna go, and if you press ‘q’ you quit lynx.
\n\u00a0You search in text with lynx with ‘\/’ and move around with
\n\u00a0the arrow keys and the TAB key.<\/p>\n

\u00a0A tips is that lynx works as a file manager, as this: lynx <\/path\/><\/p>\n

\u00a0A good usage for lynx is that you can use it as direct downloader,
\n\u00a0like this: lynx -souce ftp:\/\/ftp.bogus.com\/foo\/bar.tar.gz<\/a> > bar.tar.gz<\/p>\n

\u00a0For more help or information do: lynx –help
\n\u00a0Or: man lynx<\/p>\n

——————————————————————————-<\/p>\n

mail
\n\u00a0mail is most commonly used to just check your mail in the most
\n\u00a0simple way by just typing `mail`, but it can also be used
\n\u00a0with alot of arguments, I have personally never used
\n\u00a0any arguments to the mail command, but if you wanna check
\n\u00a0them out do: man mail<\/p>\n

——————————————————————————-<\/p>\n

man
\n\u00a0manual pages, there are several different manual pages, say for example
\n\u00a0the command exec, `man exec` should bring you little, while
\n\u00a0`man 3 exec` should bring you the C function manual on exec.<\/p>\n

\u00a0The man pages traditional way of storing is:<\/p>\n

\u00a0man1\u00a0 misc user commands
\n\u00a0man2\u00a0 C programming functions
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 man3\u00a0 more C programming functions
\n\u00a0man4\u00a0 network related manuals
\n\u00a0man5\u00a0 system related files
\n\u00a0man6\u00a0 game manuals
\n\u00a0man7\u00a0 misc technical manuals
\n\u00a0man8\u00a0 misc superuser commands
\n\u00a0man9\u00a0 misc system\/devices<\/p>\n

\u00a0I may be wrong about the category’s there, but that’s how it seems
\n\u00a0to me.
\n\u00a0Anyway, to bring up a manual page simply do: man <command>
\n\u00a0or: man <number> <command><\/p>\n

——————————————————————————-<\/p>\n

mc
\n\u00a0midnight commander is a visual shell for *nix Operating Systems.
\n\u00a0mc is quite large and has alot of arguments, I personally don’t use
\n\u00a0midnight commander at all, but if you wanna learn more about it
\n\u00a0do: man mc<\/p>\n

——————————————————————————-<\/p>\n

mesg
\n\u00a0mesg is a command with which you control if other users should
\n\u00a0have write access to your terminal, as `wall` messages, `write`
\n\u00a0or anything similar.<\/p>\n

\u00a0mesg y turns on the access for others to write to your terminal.
\n\u00a0mesg n turns off the access for others to write to your terminal.<\/p>\n

——————————————————————————-<\/p>\n

mkdir
\n\u00a0make directory, creates a directory, works as: mkdir [arguments] dir\/
\n\u00a0The arguments can be as follows:<\/p>\n

\u00a0-m, –mode=MODE\u00a0 see chmod’s octal (numerical) modes<\/p>\n

\u00a0-p, –parents\u00a0 no error if existing, make\u00a0 parent
\n\u00a0\u00a0\u00a0 directories\u00a0 as needed<\/p>\n

\u00a0–verbose\u00a0 print a message for each created directory<\/p>\n

\u00a0–help\u00a0\u00a0\u00a0 display the help and exit<\/p>\n

\u00a0–version\u00a0 output version information and exit<\/p>\n

\u00a0mkdir is most commonly used as: mkdir <newdir><\/p>\n

——————————————————————————-<\/p>\n

mknod
\n\u00a0mknod is used to create special files, as devices.
\n\u00a0mknod’s syntax is this: mknod [arguments] <name> <type> [MAJOR MINOR]
\n\u00a0It can be used with the following arguments:<\/p>\n

\u00a0-m, –mode=MODE
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 set permission mode (as in chmod), not 0666 – umask<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0 display this help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0MAJOR MINOR are forbidden for <type> p, else they must be used.<\/p>\n

\u00a0b\u00a0\u00a0\u00a0\u00a0\u00a0 create a block (buffered) special file<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c, u\u00a0\u00a0 create a character (unbuffered) special file<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 p\u00a0\u00a0\u00a0\u00a0\u00a0 create a FIFO<\/p>\n

\u00a0You need to know the devices major\/minior number if you gonna use this
\n\u00a0command, those are located in \/usr\/src\/linux\/Documentation\/devices.txt
\n\u00a0that comes with the kenrnel source.
\n\u00a0The “char” is the minior and the number before the devices are the
\n\u00a0major numbers so say that you wanna make a new \/dev\/null for some
\n\u00a0reason, then you read the devices.txt and see this:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 char\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Memory devices
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 = \/dev\/mem\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Physical memory access
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2 = \/dev\/kmem\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Kernel virtual memory access
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3 = \/dev\/null\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Null device<\/p>\n

\u00a0And so you make the null device like this:<\/p>\n

\u00a0mknod \/dev\/null b 1 3<\/p>\n

\u00a0Or if you wanna make a new \/dev\/scd device to support another
\n\u00a0emulated scsi cdrom device. (there are 7 scd devices default)
\n\u00a0So here’s how you make another:<\/p>\n

\u00a0mknod \/dev\/scd8 b 11 8<\/p>\n

\u00a0This is not as hard at all …..<\/p>\n

\u00a0for more info: info mknod
\n\u00a0or: man mknod<\/p>\n

——————————————————————————-<\/p>\n

modprobe
\n\u00a0modprobe loads modules in a similar way as depmod.
\n\u00a0See modprobe’s manual page: man modprobe<\/p>\n

——————————————————————————-<\/p>\n

more
\n\u00a0more is a command to display a files contents, it’s very similar
\n\u00a0to the `less` command.
\n\u00a0See `less` and more’s manual pages: man more<\/p>\n

——————————————————————————-<\/p>\n

mount
\n\u00a0mount, mounts a media, that is to say that you make the contents
\n\u00a0of say a hard drive visible to the system on some mountpoint,
\n\u00a0ie. mount -t vfat \/dev\/hda1 \/windows
\n\u00a0This command would mount hda1 (the first harddrive’s (hd a)
\n\u00a0first partition (hda 1), as (-t <filesystem>) vfat which is
\n\u00a0the windows native filesystem.
\n\u00a0Linux native filesystem is ext2.<\/p>\n

\u00a0mount has ALOT of arguments, if you wanna read about them all
\n\u00a0do: man mount<\/p>\n

——————————————————————————-<\/p>\n

mv
\n\u00a0mv, moves a file or directory.
\n\u00a0It works like this: mv [argument] <file-to-move> <new-name\/location>
\n\u00a0This is an example: mv \/home\/alien\/bash.tutor \/home\/old\/bash.tutor
\n\u00a0Or just to rename a file: mv bash.tutor bash.file<\/p>\n

\u00a0mv can also be executed with alot of arguments, which are:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -b, –backup
\n\u00a0 make backup before removal<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f, –force
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 remove existing destinations, never prompt<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -i, –interactive
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 prompt before overwrite<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -S, –suffix=SUFFIX
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 override the usual backup suffix<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u, –update
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 move only older or brand new non-directories<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v, –verbose
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 explain what is being done<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -V, –version-control=WORD
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 override the usual version control<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display the help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0Here’s an example: mv -f \/home\/alien\/bash.tutor \/
\n\u00a0This will by force mv the file to \/ (if you have write rights to \/)<\/p>\n

——————————————————————————-<\/p>\n

nc \/ netcat
\n\u00a0netcat is by default usually located in: \/usr\/lib\/linuxconf\/lib\/
\n\u00a0netcat is very useful in internet based shell scripts, since
\n\u00a0it can listen on a socket or send to sockets, depending on the version.
\n\u00a0the default netcat can as far as I know only send to sockets.
\n\u00a0works basicly like this:<\/p>\n

\u00a0\/usr\/lib\/linuxconf\/lib\/netcat –file <file> <ip> <port><\/p>\n

\u00a0But can be executed with the following arguments:
\n\u00a0–head <nb_lines>
\n\u00a0–tail <nb_lines>
\n\u00a0–send <file><\/p>\n

\u00a0A tip is to make one or two links from \/usr\/lib\/linuxconf\/lib\/netcat
\n\u00a0to \/usr\/local\/bin\/netcat and perhaps \/usr\/local\/bin\/nc<\/p>\n

——————————————————————————-<\/p>\n

ncftp
\n\u00a0ncftp is a very powerful ftp client.
\n\u00a0ncftp has the following syntax: ncftp [arguments] <host>
\n\u00a0If no arguments is given it will try to login as anonymous user
\n\u00a0with an e-mail as password.<\/p>\n

\u00a0Most common non-anonymous usage is this: ncftp -u <username> <host><\/p>\n

\u00a0The commands you will use the most once logged on to an ftp
\n\u00a0is the following:<\/p>\n

\u00a0get <name> download a file
\n\u00a0put <name> upload a file
\n\u00a0ls\u00a0 list current directory
\n\u00a0cd\u00a0 <dir-name> change directory
\n\u00a0lls\u00a0 list local directory
\n\u00a0lcd\u00a0 change local directory<\/p>\n

\u00a0If you want to read all ncftp’s commands and arguments do: man ncftp<\/p>\n

——————————————————————————-<\/p>\n

ncftpget
\n\u00a0ncftpget is a command line based ftp download client. It works
\n\u00a0like this: ncftpget [arguments] <host> <local-dir> <remote-files><\/p>\n

\u00a0ncftpget comes with ncftp, if you want to see all it’s commands,
\n\u00a0do: man ncftpget<\/p>\n

——————————————————————————-<\/p>\n

ncftpput
\n\u00a0ncftpput is a command line based ftp upload client. It works
\n\u00a0like this: ncftpput [arguments] <host> <remote-dir> <remote-files><\/p>\n

\u00a0ncftpput comes with ncftp, if you want to see all it’s commands,
\n\u00a0do: man ncftpput<\/p>\n

——————————————————————————-<\/p>\n

netstat
\n\u00a0netstat will show you the network connections to and from your computer
\n\u00a0that’s currently active, it can simply be used by typing `netcat`
\n\u00a0or it can me used with it’s arguments, if you wanna learn
\n\u00a0more about this command, do: man netcat<\/p>\n

——————————————————————————-<\/p>\n

nice
\n\u00a0nice is a command that can set the priority (cpu time) of a program
\n\u00a0or a command, the prioretys can be from -20 which is max priority
\n\u00a0to 19 which is the minimum priority.
\n\u00a0nice works like this: nice [argument] <command> <argument>
\n\u00a0The arguments “[argument]” for nice can be:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -ADJUST
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 increment priority by ADJUST first<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -n, –adjustment=ADJUST
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 same as -ADJUST<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0 display the help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0Example: nice -n -20 make bzImage
\n\u00a0This will make the kernel with as much CPU as it can.
\n\u00a0This means this process has more rights then any other process.<\/p>\n

\u00a0Another example is: nice -n 19 zgv
\n\u00a0This will give zgv absolutely lowest priority, and will there for
\n\u00a0be the slowest moving processes on the system, as if it runs
\n\u00a0with nice 19 and another process comes and wants more CPU power
\n\u00a0then there is free, `zgv` will in this case give the other
\n\u00a0process of it’s own power.<\/p>\n

——————————————————————————-<\/p>\n

nmap
\n\u00a0nmap is getting to come as default for some Linux distributions,
\n\u00a0and is a port scanner, maybe the best port scanner there is.<\/p>\n

\u00a0nmap is used like this: nmap [arguments] <host \/ ip>
\n\u00a0So say you want to port scan yourself you could do:
\n\u00a0nmap 127.0.0.1
\n\u00a0Or: nmap localhost
\n\u00a0The most commonly used arguments to nmap is the ‘-sS’ which
\n\u00a0is a SYN scan, and will in most cases not reveal your IP
\n\u00a0to the one that your scanning, BUT if the other side
\n\u00a0has any kind of modern logging device as a fairly new
\n\u00a0firewall or port logger your IP will be shown to him anyway.<\/p>\n

\u00a0The other perhaps next most common argument to use is the ‘-O’
\n\u00a0argument, which will give you a good guess of what the remote
\n\u00a0operating system is this function works the same as for
\n\u00a0the operating system guess program `queso`.<\/p>\n

\u00a0Example: nmap -sS -O localhost > localhost.log<\/p>\n

\u00a0The ‘> localhost.log’ part will put the outcome of the scan in a file
\n\u00a0called localhost.log.<\/p>\n

——————————————————————————-<\/p>\n

ntpdate
\n\u00a0ntpdate has no manual page nor any help page what I can found,
\n\u00a0perhaps I’ll write one if I’m bored some day …..<\/p>\n

\u00a0ntpdate will synchronize your computers system clock with an atomic
\n\u00a0clock.<\/p>\n

\u00a0ntpdate’s help usage gives this:<\/p>\n

\u00a0usage: ntpdate [-bBdqsv] [-a key#] [-e delay] [-k file] [-p samples]
\n\u00a0[-o version#] [-r rate] [-t timeo] server …<\/p>\n

\u00a0I only use it as: ntpdate <server>
\n\u00a0Like this: ntpdate ntp.lth.se<\/p>\n

——————————————————————————-<\/p>\n

ntsys \/ ntsysv
\n\u00a0runlevel confuration tool.
\n\u00a0This tool lets you configure what services that should be
\n\u00a0started with your runlevel, alteast ntsysv has a nice
\n\u00a0ncurses interface that’s easy to handle.<\/p>\n

\u00a0For moreinformation on this command do: man ntsys
\n\u00a0Or: man ntsysv
\n\u00a0Depending on your system.<\/p>\n

——————————————————————————-<\/p>\n

objdump
\n\u00a0objdump is a quite large command, that allows you to dump objects
\n\u00a0out of a binary file.
\n\u00a0To dump all objects do: objdump –source <binary file>
\n\u00a0For more info do: man objdump<\/p>\n

——————————————————————————-<\/p>\n

passwd
\n\u00a0passwd is a little tool to set a password to a user account,
\n\u00a0it basicly works like this: passwd [arguments] <username>
\n\u00a0or if you just type `passwd` you will change your own password.
\n\u00a0passwd can be sued with the following arguments:<\/p>\n

\u00a0-d, –delete\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 delete the password for the named account
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (root only)
\n\u00a0\u00a0 -f, –force\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 force operation
\n\u00a0\u00a0 -k, –keep-tokens\u00a0\u00a0 keep non-expired authentication tokens
\n\u00a0\u00a0 -l, –lock\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 lock the named account (root only)
\n\u00a0\u00a0 -S, –status\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 report password status on the named account
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (root only)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –stdin\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 read new tokens from stdin (root only)
\n\u00a0\u00a0 -u, –unlock\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 unlock the named account (root only)<\/p>\n

\u00a0Help options<\/p>\n

\u00a0-?, –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Show the help message
\n\u00a0\u00a0 –usage\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Display brief usage message<\/p>\n

\u00a0You still need to do a: man passwd<\/p>\n

——————————————————————————-<\/p>\n

patch
\n\u00a0patch simply works like this: patch <original-file> <patch-file>
\n\u00a0A patch is done with the `diff` command as
\n\u00a0this: diff file1 file2 > patchfile
\n\u00a0So then to make file1 identical to file2: patch file1 patchfile<\/p>\n

\u00a0patch can however be used with a whole lot of arguments,
\n\u00a0if you are interested do: man patch
\n\u00a0Or: patch –help<\/p>\n

——————————————————————————-<\/p>\n

pidof
\n\u00a0pidof simply gives the PID of a running process without you having
\n\u00a0to use “ps”, say that you want to find out what pid your init has,
\n\u00a0(it will always be one for the init), then you do: pidof init
\n\u00a0Or if you wanna find out which pids are used by the web server (httpd)
\n\u00a0then you do: pidof httpd
\n\u00a0So basically you find out the pids from the process name(s).<\/p>\n

\u00a0pidof has the following switches:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s\u00a0\u00a0\u00a0\u00a0 Single shot – this instructs the program to only return one pid.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -x\u00a0\u00a0\u00a0\u00a0 Scripts too – this causes the program to also return process
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 id’s of shells running the named scripts.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -o\u00a0\u00a0\u00a0\u00a0 Tells pidof to omit processes with that process id.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The special pid %PPID can be used to name the parent process of
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the pidof program, in other words the calling shell or shell
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 script.<\/p>\n

\u00a0For more info see: man pidof<\/p>\n

——————————————————————————-<\/p>\n

ping
\n\u00a0ping is a pretty basic command, that will work
\n\u00a0as: ping [arguments] <ip-or-host>
\n\u00a0The arguments can be as follows:<\/p>\n

\u00a0-c\u00a0 <number> count pings to send
\n\u00a0-d\u00a0 debug
\n\u00a0-f ping flood
\n\u00a0-i <number> wait number of seconds between each ping
\n\u00a0-l <number> preload number of pings
\n\u00a0-n numeric IP’s only
\n\u00a0-p pattern (in hex) to send as pad code in the ping header
\n\u00a0-q quiet
\n\u00a0-R\u00a0\u00a0\u00a0\u00a0\u00a0 record route
\n\u00a0-s\u00a0 <number> packet size in bytes
\n\u00a0-v\u00a0\u00a0\u00a0\u00a0\u00a0 Verbose output<\/p>\n

\u00a0So say that you wanna send 5 pings that’s 128 bytes each to
\n\u00a0IP 127.0.0.1, then you would do: ping -s 128 -c 5 127.0.0.1<\/p>\n

——————————————————————————-<\/p>\n

pmake
\n\u00a0pmake is *BSD make (so I’m told), see make and: man pmake<\/p>\n

——————————————————————————-<\/p>\n

pnpdump
\n\u00a0pnpdump gives a dump of all ISA pnp devices, good to use
\n\u00a0with isapnp etc.
\n\u00a0This is the command you wanna have a look at if your either
\n\u00a0looking for exact info of some ISA device that is pnp, or
\n\u00a0if your system has problems finding a ISA pnp device.
\n\u00a0See the manual pages.<\/p>\n

——————————————————————————-<\/p>\n

portmap
\n\u00a0portmap is the server that maps all RPC services, so if you
\n\u00a0wanna use any RPC service you wanna have portmap running.
\n\u00a0For more info: man portmap<\/p>\n

——————————————————————————-<\/p>\n

ps
\n\u00a0ps gives you the process list, as in showing you the running
\n\u00a0processes with there pid and other info.
\n\u00a0do: ps –help
\n\u00a0or: man ps for more info on what arguments it can be executed
\n\u00a0with, personally I use: `ps aux` and `ps x` the most.<\/p>\n

——————————————————————————-<\/p>\n

pstree
\n\u00a0process tree, a bit more (ascii) graphical version of ps,
\n\u00a0do: pstree –help
\n\u00a0or: man pstree
\n\u00a0for more help on the arguments, personally I use it alone without
\n\u00a0arguments.<\/p>\n

——————————————————————————-<\/p>\n

pwd
\n\u00a0print working directory, shows you your current directory.
\n\u00a0This command can be useful for 2 things what I know of,
\n\u00a0one is to show you where you are, and the other in scripts
\n\u00a0to do say: echo “output will go to: `pwd`\/logfile”<\/p>\n

——————————————————————————-<\/p>\n

quota
\n\u00a0quota prints the users quota, it works like
\n\u00a0this: quota [arguments] <user\/group>
\n\u00a0Where the arguments can be:<\/p>\n

\u00a0-g\u00a0\u00a0\u00a0\u00a0\u00a0 Print group quotas for the group of which the\u00a0 user
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is a member.\u00a0 The optional<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u\u00a0\u00a0\u00a0\u00a0\u00a0 flag is equivalent to the default.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0\u00a0 will display quotas on filesystems where no storage
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is allocated.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -q\u00a0\u00a0\u00a0\u00a0\u00a0 Print a more terse message, containing only\u00a0 infor-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 mation on filesystems where usage is over quota.<\/p>\n

\u00a0For more info on the quota command do: man quota<\/p>\n

——————————————————————————-<\/p>\n

quotaoff
\n\u00a0quotaoff turns the quota off for a file system.
\n\u00a0quotaoff works like this: quotaoff [arguments] <filesystem>
\n\u00a0The arguments can be as follows:<\/p>\n

\u00a0-a\u00a0\u00a0\u00a0\u00a0\u00a0 Force\u00a0 all file systems in \/etc\/fstab to have their
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 quotas disabled.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0\u00a0 Display a message for each file system affected.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u\u00a0\u00a0\u00a0\u00a0\u00a0 Manipulate user quotas. This is the default.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -g\u00a0\u00a0\u00a0\u00a0\u00a0 Manipulate group quotas.<\/p>\n

\u00a0This command is close to quotaon.<\/p>\n

\u00a0For more info: man quotaon
\n\u00a0(Don’t think there is a quotaoff man page, quotaon and quotaoff
\n\u00a0seems to have the same manual page)<\/p>\n

——————————————————————————-<\/p>\n

quotaon
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 quotaon turns the quota on for a file system.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 quotaon works like this: quotaon [arguments] <filesystem>
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The arguments can be as follows:<\/p>\n

\u00a0-a\u00a0\u00a0\u00a0\u00a0\u00a0 All file systems in\u00a0 \/etc\/fstab\u00a0 marked\u00a0 read-write
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 with quotas will have their quotas turned on.\u00a0 This
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is normally used at boot time to enable quotas.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0\u00a0 Display a message for each file system where quotas
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 are turned on.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u\u00a0\u00a0\u00a0\u00a0\u00a0 Manipulate user quotas. This is the default.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -g\u00a0\u00a0\u00a0\u00a0\u00a0 Manipulate group quotas.<\/p>\n

\u00a0For more info: man quotaon<\/p>\n

——————————————————————————-<\/p>\n

quotastats
\n\u00a0quotastats displays the quota stats …. cant find any help, –help
\n\u00a0or manual page for it.<\/p>\n

——————————————————————————-<\/p>\n

read
\n\u00a0read, reads a variable.<\/p>\n

\u00a0Example:<\/p>\n

\u00a0echo -n “password: ”
\n\u00a0read pass
\n\u00a0echo “Password was: $pass”<\/p>\n

\u00a0For more info: help read<\/p>\n

——————————————————————————-<\/p>\n

reboot
\n\u00a0reboot does what it says, it reboots the system, you have to be root
\n\u00a0to use this command.
\n\u00a0reboot works the same as: shutdown -r now
\n\u00a0or also the same as if you press: Ctrl+Alt+Del
\n\u00a0Nothing much more to say about the reboot command.<\/p>\n

——————————————————————————-<\/p>\n

reset
\n\u00a0reset resets the console, say that you have accidently done
\n\u00a0cat <binary-file> so you totally screwed up your console
\n\u00a0and you cant read anything on it, then just type `reset`
\n\u00a0and press enter, and it should be back to normal within some seconds.<\/p>\n

——————————————————————————-<\/p>\n

rlogin
\n\u00a0remote login, if you wanna use this command do: man rlogin
\n\u00a0bore using it.
\n\u00a0The most common use of it is: rlogin -l <username> <host><\/p>\n

——————————————————————————-<\/p>\n

rm
\n\u00a0remove, remove\/unlink files, rm can be used with the
\n\u00a0following arguments:<\/p>\n

\u00a0\u00a0 -d, –directory\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 unlink directory, even if non-empty
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (super-user only)
\n\u00a0\u00a0 -f, –force\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ignore nonexistent files, never prompt
\n\u00a0\u00a0 -i, –interactive\u00a0\u00a0\u00a0\u00a0 prompt before any removal
\n\u00a0\u00a0 -r, -R, –recursive\u00a0\u00a0 remove the contents of directories recursively
\n\u00a0\u00a0 -v, –verbose\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 explain what is being done
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0An example is, that if you have a directory called \/foo
\n\u00a0that you wanna delete recursively, then you do: rm -rf \/foo
\n\u00a0Or say that you have a file \/foo\/bar that you wanna remove
\n\u00a0without being prompted, then you do it like this: rm -f \/foo\/bar
\n——————————————————————————-<\/p>\n

rmmod
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 remove modules, remove a loaded module.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 List the modules that you can remove with lsmod.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 And load modules with insmod.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 man any of them for more information.<\/p>\n

——————————————————————————-<\/p>\n

route
\n\u00a0route, displays the routing table by default.
\n\u00a0The most common way of adding a route is like this:
\n\u00a0route add -host <ip> gw <other-ip><\/p>\n

\u00a0And to remove a post:
\n\u00a0route del -host <ip> gw <other-ip><\/p>\n

\u00a0An example would be, say that you want to route IP 123.123.123.123
\n\u00a0to 127.0.0.1, this would drop any connection attempts from
\n\u00a0123.123.123.123 to 127.0.0.1 so he cant connect to you or scan you,
\n\u00a0(this is true in most cases), you would do:<\/p>\n

\u00a0route add -host 123.123.123.123 gw 127.0.0.1<\/p>\n

\u00a0Now the route command is bigger then that, so if you wanna
\n\u00a0learn more about it do: man route<\/p>\n

——————————————————————————-<\/p>\n

rpm
\n\u00a0rpm is a command that is is very important to most distributions.
\n\u00a0rpm is short for ‘redhat package manager’ and was developed for
\n\u00a0RedHat by Caldera.
\n\u00a0rpm is a HUGE command, and works like this: rpm [arguments] <file>
\n\u00a0but here are the most commonly used arguments:<\/p>\n

\u00a0rpm -ivh <package.rpm> installs package.rpm
\n\u00a0rpm -Uvh <package.rpm> updates package.rpm
\n\u00a0rpm -e <package> un-installed\/erases package
\n\u00a0rpm -qf <file>\u00a0 displays what package the file came with
\n\u00a0rpm -qlp <package.rpm> displays the contents of the package.rpm
\n\u00a0rpm -qRp <package.rpm>\u00a0 displays the dependencys needed by package.rpm<\/p>\n

\u00a0Other arguments and that are commonly used but not recommended are:<\/p>\n

\u00a0–force\u00a0 force install something
\n\u00a0–nodeps do not check dependences<\/p>\n

\u00a0Another thing is if you installed a *.src.rpm file (that ends up in
\n\u00a0\/usr\/src\/RPM\/*), you can compile a binary .rpm from it.
\n\u00a0Say that you installed some-package.src.rpm, then you would go to:
\n\u00a0\/usr\/src\/RPM\/SPECS\/, and there type: rpm -ba some-package.spec
\n\u00a0wait a while during the compile, and then you would have a
\n\u00a0\/usr\/src\/RPM\/RPMS\/<platform>\/some-package.<platform>.rpm<\/p>\n

\u00a0the “<platform>” is your platform, as i386, i486, i586, i686,
\n\u00a0k6, ppc, sprac, noarch etc.<\/p>\n

\u00a0To create an rpm from a .src.rpm you first need to know that
\n\u00a0this should not be done as root for the simple reason that
\n\u00a0if you make an rpm as root several unworking parts of it may
\n\u00a0remain in your system generating errors if the compile of
\n\u00a0the rpm isnt successful.<\/p>\n

\u00a0So the first thing you do to do this as user is to create a file
\n\u00a0named .rpmmacros
\n\u00a0And in that add the following:
\n\u00a0%_topdir\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ~\/RPM<\/p>\n

\u00a0This should work to create the file:
\n\u00a0echo “%_topdir\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 $HOME\/RPM” > ~\/.rpmmacros<\/p>\n

\u00a0Then you do this:
\n\u00a0mkdir -p ~\/RPM\/{SOURCES,SPECS,BUILD,RPMS,SRPMS}<\/p>\n

\u00a0Now you’re ready to start to build an rpm from a .src.rpm
\n\u00a0first (as user, not as root) install the source rpm.<\/p>\n

\u00a0rpm -ivh package.src.rpm<\/p>\n

\u00a0Then you go to ~\/RPM\/SPECS\/<\/p>\n

\u00a0The .src.rpm should have installed the sources in ~\/RPM\/SOURCES
\n\u00a0and the spec file in ~\/RPM\/SPECS\/
\n\u00a0The spec file is like a script file, it tells rpm how to compile
\n\u00a0the source and build the rpm.<\/p>\n

\u00a0Now find the spec file in ~\/RPM\/SPECS\/, it’s usually named the same
\n\u00a0as the package, like this:<\/p>\n

\u00a0package.spec<\/p>\n

\u00a0So not to make an rpm out of it, do this:<\/p>\n

\u00a0rpm -ba package.spec<\/p>\n

\u00a0If this is successful (which it sadly enough isnt every time because
\n\u00a0of ill written spec files)
\n\u00a0You should now have an rpm file in ~\/RPM\/RPMS\/<your architecture><\/p>\n

\u00a0If you have a Pentium 2, the arch command will show “i586” and
\n\u00a0so the rpm will be found in ~\/RPM\/RPMS\/i586\/<\/p>\n

\u00a0You will also have a brand new .src.rpm in ~\/RPM\/SRPMS\/<\/p>\n

\u00a0If you need to do the rpm to any other target then your own
\n\u00a0architecture, say you want to do it for i386, then you may do:<\/p>\n

\u00a0rpm -ba package.spec –target=i386<\/p>\n

\u00a0And so the new rpm will be found in ~\/RPM\/RPMS\/i386\/
\n\u00a0This is about all there is to say about the rpm command in this
\n\u00a0tutorial.
\n\u00a0The rpm command and the spec file *scripting* langauge
\n\u00a0would need a rather large tutorial by it self to be explained
\n\u00a0in full …. so I wont take up all that here.<\/p>\n

\u00a0For more info on the rpm command do: man rpm<\/p>\n

——————————————————————————-<\/p>\n

sed
\n\u00a0sed, stream editor, is already breafly explained in this tutorial,
\n\u00a0so if you want more info do: man sed<\/p>\n

——————————————————————————-<\/p>\n

setleds
\n\u00a0setleds may show or set the flags and lights on NumLock, CapsLock
\n\u00a0and ScrollLock.
\n\u00a0On it’s own without any arguments it shows the current settings.<\/p>\n

\u00a0The syntax is this: setleds [arguments] <+\/-num,caps,scroll><\/p>\n

\u00a0Here’s the arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -F This\u00a0 is the default. Only change the VT flags (and
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 their setting may\u00a0 be\u00a0 reflected\u00a0 by\u00a0 the\u00a0 keyboard
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 leds).<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -D\u00a0\u00a0\u00a0\u00a0\u00a0 Change both the VT flags and their default settings
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (so that a\u00a0 subsequent\u00a0 reset\u00a0 will\u00a0 not\u00a0 undo\u00a0 the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 change). This might be useful for people who always
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 want to have numlock set.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -L\u00a0\u00a0\u00a0\u00a0\u00a0 Do not touch the VT\u00a0 flags,\u00a0 but\u00a0 only\u00a0 change\u00a0 the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 leds.\u00a0 From this moment on, the leds will no longer
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 reflect the VT flags (but display whatever\u00a0 is\u00a0 put
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 into them). The command setleds -L (without further
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 arguments) will restore the situation in which\u00a0 the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 leds reflect the VT flags.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -num +num
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Clear\u00a0 or\u00a0 set\u00a0 NumLock.\u00a0\u00a0 (At present, the NumLock
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 setting influences\u00a0 the\u00a0 interpretation\u00a0 of\u00a0 keypad
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 keys.\u00a0\u00a0 Pressing\u00a0 the\u00a0 NumLock\u00a0 key complements the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NumLock setting.)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -caps +caps
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Clear or set CapsLock.\u00a0 (At present,\u00a0 the\u00a0 CapsLock
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 setting\u00a0 complements\u00a0 the Shift key when applied to
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 letters.\u00a0 Pressing the CapsLock key complements the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 CapsLock setting.)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -scroll +scroll
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Clear or set ScrollLock.\u00a0 (At present, pressing the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ScrollLock key (or ^S\/^Q) stops\/starts console out-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 put.)<\/p>\n

\u00a0Here is a few example, where the first one is from the manualpage,
\n\u00a0(I’d hate to break the cut’n’paste tradition from the manual pages
\n\u00a0now), so here are some examples:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 INITTY=\/dev\/tty[1-8]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 for tty in $INITTY; do
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 setleds -D +num < $tty
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 done<\/p>\n

\u00a0This would set numlock on for tty1 to tty8<\/p>\n

\u00a0Here’s another short example:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 while \/bin\/true; do
\n\u00a0\u00a0\u00a0\u00a0\u00a0 setleds -L +caps; usleep 500000
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 setleds -L +num; usleep 500000
\n\u00a0\u00a0\u00a0\u00a0\u00a0 setleds -L -caps; usleep 500000
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 setleds -L -num; usleep 500000
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 done<\/p>\n

\u00a0This would flash the NumLock and CapsLock leds, for infinety.<\/p>\n

\u00a0For more info do: man setleds<\/p>\n

——————————————————————————-<\/p>\n

seq
\n\u00a0sequence numbers.
\n\u00a0seq works baskically like this:<\/p>\n

\u00a0seq [OPTION] LAST
\n\u00a0seq [OPTION] FIRST LAST
\n\u00a0seq [OPTION] FIRST INCREMENT LAST<\/p>\n

\u00a0And can be used with the following options:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f, –format FORMAT\u00a0\u00a0\u00a0\u00a0\u00a0 use printf(3) style FORMAT (default: %g)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s, –separator STRING\u00a0\u00a0 use STRING to separate numbers (default: \\n)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -w, –equal-width\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 equalize width by padding with leading zeroes
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0Here’s some small examples and what they do:<\/p>\n

\u00a0seq 10\u00a0 (Count from 1 to 10)
\n\u00a0seq 5 10 (Count from 5 to 10)
\n\u00a0seq 1 2 10 (Count from 1 to 10 by incrementing two: 1,3,5,7,9)
\n\u00a0seq 10 0 (Count backwards from 10 to 0)<\/p>\n

\u00a0For more info do: seq –help<\/p>\n

——————————————————————————-<\/p>\n

sleep
\n\u00a0sleep works like this: sleep <number of seconds>
\n\u00a0Not much to say about this command, … if you wanna read
\n\u00a0more about it: man sleep<\/p>\n

——————————————————————————-<\/p>\n

sort
\n\u00a0sort, sorts the contents of a file and gives the output to stdout.
\n\u00a0By default it sorts it in alphabetical order, sort works
\n\u00a0like this: sort [arguments] <file><\/p>\n

\u00a0sort can be executed with the following arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -b\u00a0\u00a0\u00a0\u00a0\u00a0 ignore leading blanks in sort fields or keys<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c\u00a0\u00a0\u00a0\u00a0\u00a0 check if given files already sorted, do not sort<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -d\u00a0\u00a0\u00a0\u00a0\u00a0 consider only [a-zA-Z0-9 ] characters in keys<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f\u00a0\u00a0\u00a0\u00a0\u00a0 fold lower case to upper case characters in keys<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -g\u00a0\u00a0\u00a0\u00a0\u00a0 compare according to general numerical value, imply -b<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -i\u00a0\u00a0\u00a0\u00a0\u00a0 consider only [ 40- 176] characters in keys<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -k POS1[,POS2]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 start a key at POS1, end it *at* POS2
\n\u00a0 field\u00a0 numbers\u00a0 and\u00a0 character offsets are numbered
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 starting with one (contrast\u00a0 with\u00a0 zero-based\u00a0 +POS form)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -m\u00a0\u00a0\u00a0\u00a0\u00a0 merge already sorted files, do not sort<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -M\u00a0\u00a0\u00a0\u00a0\u00a0 compare (unknown) < `JAN’ < … < `DEC’, imply -b<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -n\u00a0\u00a0\u00a0\u00a0\u00a0 compare\u00a0 according to string numerical value, imply -b<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -o FILE
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 write result on FILE instead of standard output<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -r\u00a0\u00a0\u00a0\u00a0\u00a0 reverse the result of comparisons<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s\u00a0\u00a0\u00a0\u00a0\u00a0 stabilize sort by disabling last resort comparison<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -t SEP\u00a0 use SEParator instead of non- to whitespace transition<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -T DIRECTORY
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 use\u00a0 DIRECTORY\u00a0 for temporary files, not $TMPDIR or \/tmp<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u\u00a0\u00a0\u00a0\u00a0\u00a0 with -c, check for strict ordering; with\u00a0 -m,\u00a0 only
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output the first of an equal sequence<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -z\u00a0\u00a0\u00a0\u00a0\u00a0 end\u00a0 lines\u00a0 with\u00a0 0\u00a0 byte,\u00a0 not\u00a0 newline,\u00a0 for find -print0<\/p>\n

\u00a0–help\u00a0\u00a0 display the help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version output version information and exit<\/p>\n

\u00a0One more time I give thanks to the cut & paste function.<\/p>\n

\u00a0Here’s an example of sort: sort file1 -o sorted-file2
\n\u00a0This command works good with the `uniq` command to sort out
\n\u00a0duplica words, like this: sort file1 | uniq > sorted-file<\/p>\n

\u00a0For more info do: man sort<\/p>\n

——————————————————————————-<\/p>\n

ssh
\n\u00a0secure shell, works a bit like telnet but has encryption,
\n\u00a0ssh is becoming a good standard of encrypted remote shell connections.
\n\u00a0ssh is however not usually default included in any distros,
\n\u00a0and there is several versions of it, so if you download it
\n\u00a0make sure to read all documentations about it.
\n\u00a0Even though it’s not default included, I still wanned to include it
\n\u00a0in this tutorial to make users that use LAN connections
\n\u00a0as local networks with more then one user or cable modems aware
\n\u00a0of this tool, because if they use telnet anyone on the local
\n\u00a0subnet can sniff the connection and get any login and password
\n\u00a0used with incoming or outgoing telnet connections.
\n\u00a0Really anyone can sniff anything that’s not encrypted, like
\n\u00a0ftp logins and passwords, http, IRC, and everything like that.
\n\u00a0but the most vital to protect is the ways people can enter
\n\u00a0your system, so if you are on a LAN with more then one user
\n\u00a0or have any form of cable or non-dialup connection,
\n\u00a0then disable telnet (put a # in front of the telnet line in
\n\u00a0\/etc\/initd.conf and after that do: killall -HUP initd), and then
\n\u00a0install ssh.<\/p>\n

——————————————————————————-<\/p>\n

strip
\n\u00a0strip strips binary files (executables) of junk code,
\n\u00a0such as debugging information.
\n\u00a0This may be very useful to bring down the size of executable files.
\n\u00a0BUT beware, if you strip the kernel or any other very complex
\n\u00a0binary, they are likely to malfunction, so use this command
\n\u00a0wisely, and read it’s manual page.<\/p>\n

——————————————————————————-<\/p>\n

su
\n\u00a0su, the manual pages says substitute user and the UNIX command bible
\n\u00a0says super user … so it means any of those, it’s however used
\n\u00a0to *become another user*, if you are root and su <user> you wont
\n\u00a0need to supply any password.
\n\u00a0If you type only `su` as user you will become root if you have the
\n\u00a0aproperiet root password.
\n\u00a0su can be used with the following arguments:<\/p>\n

\u00a0-, -l, –login\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 make the shell a login shell
\n\u00a0\u00a0 -c, –commmand=COMMAND\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 pass a single COMMAND to the shell with -c
\n\u00a0\u00a0 -f, –fast\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 pass -f to the shell (for csh or tcsh)
\n\u00a0\u00a0 -m, –preserve-environment\u00a0\u00a0 do not reset environment variables
\n\u00a0\u00a0 -p\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 same as -m
\n\u00a0\u00a0 -s, –shell=SHELL\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 run SHELL if \/etc\/shells allows it
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0Say now that you wanna su to root and have root’s path\/enviorment.
\n\u00a0then you do: su –
\n\u00a0Or say that you wanna execute a single command as root from being
\n\u00a0a user, say the command `adduser`, then you do: su -c “adduser”
\n\u00a0you will be prompted for the password, and if you can supply it
\n\u00a0the command will be executed as root.<\/p>\n

——————————————————————————-<\/p>\n

swapoff
\n\u00a0turns swap off, it can be used with the following arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -h\u00a0\u00a0\u00a0\u00a0 Provide help
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -V\u00a0\u00a0\u00a0\u00a0 Display version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s\u00a0\u00a0\u00a0\u00a0 Display\u00a0 swap usage summary by device.\u00a0 This option
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is only available if \/proc\/swaps\u00a0 exists\u00a0 (probably
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 not before kernel 2.1.25).
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -a\u00a0\u00a0\u00a0\u00a0 All\u00a0 devices\u00a0 marked\u00a0 as\u00a0 “sw”\u00a0 swap\u00a0 devices\u00a0 in
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/etc\/fstab are made available.
\n\u00a0-p priority (man swapon and swapoff for more info on prioretys)<\/p>\n

\u00a0Example, say that you wanna turn all swap partitions (from \/etc\/fstab)
\n\u00a0off then you do: swapoff -a
\n\u00a0Again, for more info: man swapoff<\/p>\n

——————————————————————————-<\/p>\n

swapon
\n\u00a0swapon is the opposite of swapoff but has the same arguments.
\n\u00a0See: man swapon<\/p>\n

——————————————————————————-<\/p>\n

tail
\n\u00a0tail gives by default the last 10 lines out of a file, it’s very alike
\n\u00a0the `head` command, ad works like this: tail [arguments] <file>
\n\u00a0The most common usage of tail is this:<\/p>\n

\u00a0tail -f <file> This will append the data to stdout as the file grows.
\n\u00a0\u00a0 very good to view logs as they come in.<\/p>\n

\u00a0tail -50 <file> Displays the last 50 lines from a file.<\/p>\n

\u00a0tail has more arguments which you can learn in it’s manual page
\n\u00a0if you are interested, do: man tail<\/p>\n

——————————————————————————-<\/p>\n

talk
\n\u00a0talk is a little daemon controlled by inetd, so if it doesn’t
\n\u00a0work on your local machine make sure the talk line in
\n\u00a0\/etc\/inetd.cond are not remmed by a leading # character.<\/p>\n

\u00a0Talk gives a real time text chat, in a horizontally divided
\n\u00a0window or rather console.<\/p>\n

\u00a0Talk works like this: talk user@host<\/a>
\n\u00a0or just user if it’s on the local machine.
\n\u00a0Say that I wanna send a talk request to user `alfa` on IP
\n\u00a0123.123.123.132, and I’m user `beta` on 234.234.234.234.
\n\u00a0Then I type: talk alfa@123.123.123.132<\/a>
\n\u00a0And he as answer when the request comes
\n\u00a0types: talk beta@234.234.234.234<\/a><\/p>\n

\u00a0What to type as answer comes up when you get a talk request.<\/p>\n

\u00a0For more info on the talk command do: man talk<\/p>\n

——————————————————————————-<\/p>\n

tar
\n\u00a0tar, UNIX tape archive, is yet another huge command,
\n\u00a0it’s used to compress a directory to a compressed .tar file,
\n\u00a0or a single file to a tar file.
\n\u00a0tar works like this: tar [arguments] <directory-or-file><\/p>\n

\u00a0Here are the most common examples of tar usage:<\/p>\n

\u00a0tar -zvxf <file.tar.gz> uncompress a .tar.gz or .tgz archive
\n\u00a0tar -vxf <file.tar> uncompress a .tar archive
\n\u00a0tar -c –file=<file.tar> <directory> crates a .tar archive
\n\u00a0tar -cf <file.tar> <directory>\u00a0\u00a0\u00a0 – same as above –
\n\u00a0tar -tf <file.tar> list the contents of a .tar file
\n\u00a0tar -tzf <file.tar.gz> list the contents of a .tar.gz or a .tgz file
\n\u00a0tar -czvf <file.tar.gz> <directory> crates a .tar.gz archive<\/p>\n

\u00a0For more info on the tar command, do: man tar<\/p>\n

——————————————————————————-<\/p>\n

tcpdump
\n\u00a0tcpdump is a command that let’s you view the traffic on the local
\n\u00a0subnet or segment, It’s not default on many Linux distributions.
\n\u00a0So if you have it or get it, read it’s documentation and it’s
\n\u00a0manual pages, if you want to use it.<\/p>\n

——————————————————————————-<\/p>\n

telnet
\n\u00a0telnet is the most basic of all clients to know.
\n\u00a0It’s not often you will ever use it in other ways
\n\u00a0then: telnet <host-or-ip> <port>
\n\u00a0And it’s not even so often one uses it with the port number after.<\/p>\n

\u00a0Telnet creates a real time connection to another computer,
\n\u00a0ofcorse the other computer needs a running telnet daemon,
\n\u00a0and you need to have a login and a password to get in.
\n\u00a0But when you get in you can remotely work on the other system
\n\u00a0just as if you sat in front of it.<\/p>\n

\u00a0Times when it’s good to supply a port number after the host is
\n\u00a0most commonly to check the version of some daemon\/server,
\n\u00a0as if you want to know the version of your own sendmail, you
\n\u00a0can always do: telnet 127.0.0.1 25
\n\u00a0smtp (send mail transfer protocol) runs on port 25.
\n\u00a0If you wonder what port something runs on check in \/etc\/services<\/p>\n

\u00a0For more info on telnet do: man telnet<\/p>\n

——————————————————————————-<\/p>\n

test
\n\u00a0test is a big command, and is used to generate boolean results
\n\u00a0out of 2 arguments, to explain the whole command here would take up
\n\u00a0to much space and time, it can be used like this:<\/p>\n

\u00a0test -f \/sbin\/shutdown && echo “It’s there” || echo “It’s not there”<\/p>\n

\u00a0That line says in clear english:
\n\u00a0test if file \/sbin\/shutdown is there, if outcome is true
\n\u00a0echo “It’s there” else echo “It’s not there”.<\/p>\n

\u00a0You can test if a file is executeble, if a string is non-zero etc.
\n\u00a0Just about anything you can think of.<\/p>\n

\u00a0For more info on the many things you can do with the `test`
\n\u00a0command, do: man test<\/p>\n

——————————————————————————-<\/p>\n

touch
\n\u00a0touch will by default change the date on a file to the current date.
\n\u00a0It works like this: touch [arguments] <file>
\n\u00a0If the file doesn’t exist if will create a file that’s 0 bytes big.<\/p>\n

\u00a0The following arguments can be used with touch:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -a\u00a0\u00a0\u00a0\u00a0\u00a0 change only the access time<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c\u00a0\u00a0\u00a0\u00a0\u00a0 do not create any files<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -d, –date=STRING
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 parse STRING and use it instead of current time<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f\u00a0\u00a0\u00a0\u00a0\u00a0 (ignored)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -m\u00a0\u00a0\u00a0\u00a0\u00a0 change only the modification time<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -r, –reference=FILE
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 use this file’s times instead of current time<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -t\u00a0\u00a0\u00a0\u00a0 STAMP
\n\u00a0 use [[CC]YY]MMDDhhmm[.ss] instead of current time<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –time=WORD
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 access -a, atime -a, mtime -m, modify -m, use -a<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0 display the help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0So say that you have a file called ‘file’ that I want to change date of
\n\u00a0to say ‘Aug 21 1999 04:04′,
\n\u00a0then you would do: touch -t 9908210404 file<\/p>\n

\u00a0For more info on this command do: man touch<\/p>\n

——————————————————————————-<\/p>\n

tr
\n\u00a0translate characters, this command can change all upper case
\n\u00a0characters to lower case characters in a file or substitute
\n\u00a0all mumbers to some other characters etc.
\n\u00a0tr’s syntax is: tr [arguments] <SET1> <SET2>
\n\u00a0tr can be used with the following arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c, –complement
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 first complement SET1<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -d, –delete
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 delete characters in SET1, do not translate<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s, –squeeze-repeats
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 replace sequence of characters with one<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -t, –truncate-set1
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 first truncate SET1 to length of SET2<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0 display this help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0And the SET’s are as follows:<\/p>\n

\u00a0[:alnum:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all letters and digits<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:alpha:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all letters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:blank:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all horizontal whitespace<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:cntrl:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all control characters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:digit:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all digits<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:graph:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all printable characters, not including space<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:lower:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all lower case letters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:print:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all printable characters, including space<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:punct:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all punctuation characters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:space:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all horizontal or vertical whitespace<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:upper:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all upper case letters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [:xdigit:]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all hexadecimal digits<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [=CHAR=]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all characters which are equivalent to CHAR<\/p>\n

\u00a0Examples of tr is:
\n\u00a0cat file | tr [:upper:] [:lower:] (change all uppercase to lower)
\n\u00a0cat file | tr -d [:alnum:]\u00a0 (delete all numbers and chars)<\/p>\n

\u00a0For more info on tr, do: man tr<\/p>\n

——————————————————————————-<\/p>\n

traceroute
\n\u00a0traceroute is a command that traces a route to an IP\/host
\n\u00a0and will give you the number of hops from your computer
\n\u00a0to the remote computer, and will display the ping times
\n\u00a0to each computer in the way.<\/p>\n

\u00a0traceroute has some arguments that I never needed to use
\n\u00a0but if you feel curious about this command, feel free
\n\u00a0to look at the manual pages for it: man traceroute<\/p>\n

——————————————————————————-<\/p>\n

ulimit
\n\u00a0ulimit sets a limit for how much memory etc. users are allowed
\n\u00a0to use.
\n\u00a0It works like this: ulimit [arguments]
\n\u00a0And the arguments can be the following:<\/p>\n

\u00a0 -S\u00a0\u00a0\u00a0\u00a0 use the `soft’ resource limit
\n\u00a0 -H\u00a0\u00a0\u00a0\u00a0 use the `hard’ resource limit
\n\u00a0 -a\u00a0\u00a0\u00a0\u00a0 show all settings
\n\u00a0 -c\u00a0\u00a0\u00a0\u00a0 core file size (in blocks)
\n\u00a0 -d\u00a0\u00a0\u00a0\u00a0 data seg size (in kilo bytes)
\n\u00a0 -f\u00a0\u00a0\u00a0\u00a0 file size (in blocks)
\n\u00a0 -l\u00a0\u00a0\u00a0\u00a0 max locked memory (in kilo bytes)
\n\u00a0 -m\u00a0\u00a0\u00a0\u00a0 max memory size (in kilo bytes)
\n\u00a0 -n\u00a0\u00a0\u00a0\u00a0 open files (number)
\n\u00a0 -p\u00a0\u00a0\u00a0\u00a0 pipe size (512 bytes)
\n\u00a0 -s\u00a0\u00a0\u00a0\u00a0 stack size (in kilo bytes)
\n\u00a0 -t\u00a0\u00a0\u00a0\u00a0 cpu time (in seconds)
\n\u00a0 -u\u00a0\u00a0\u00a0\u00a0 max user processes (number)
\n\u00a0 -v\u00a0\u00a0\u00a0\u00a0 virtual memory (kilo bytes)<\/p>\n

\u00a0Say that I want to set a limit that users can only run 50
\n\u00a0processes each, the I would do: ulimit -u 50<\/p>\n

——————————————————————————-<\/p>\n

umount
\n\u00a0un mount, un mounts a mountpoint, say that you have mounted your
\n\u00a0CD-rom drive on \/mnt\/cdrom then you would do: umount \/mnt\/cdrom
\n\u00a0to unmount it.<\/p>\n

\u00a0I never used any arguments to this command, but if you wanna learn
\n\u00a0about them, feel free to do: man umount<\/p>\n

——————————————————————————-<\/p>\n

unalias
\n\u00a0unalias removes a defined alias, say that you have an alias
\n\u00a0like this: alias du=’du -h’
\n\u00a0And you want to remove it: then you simply do: unalias du
\n\u00a0To remove all aliases do: unalias -a<\/p>\n

\u00a0For more info do: help unalias<\/p>\n

——————————————————————————-<\/p>\n

uname
\n\u00a0uname gives info on the current system, and works as
\n\u00a0this: uname [arguments]
\n\u00a0The arguments can be the following:<\/p>\n

\u00a0\u00a0 -a, –all\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print all information
\n\u00a0\u00a0 -m, –machine\u00a0\u00a0\u00a0\u00a0 print the machine (hardware) type
\n\u00a0\u00a0 -n, –nodename\u00a0\u00a0\u00a0 print the machine’s network node hostname
\n\u00a0\u00a0 -r, –release\u00a0\u00a0\u00a0\u00a0 print the operating system release
\n\u00a0\u00a0 -s, –sysname\u00a0\u00a0\u00a0\u00a0 print the operating system name
\n\u00a0\u00a0 -p, –processor\u00a0\u00a0 print the host processor type
\n\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print the operating system version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0The most common way of using uname is: uname -a<\/p>\n

——————————————————————————-<\/p>\n

uncompress
\n\u00a0uncompress uncompresses .Z files, for more info do: man uncompress<\/p>\n

——————————————————————————-<\/p>\n

uniq
\n\u00a0uniq does by default take away duplica words out of a text,
\n\u00a0which can be good if your sorting out a dictionary.
\n\u00a0But `uniq` can also be executed with the following arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c, –count
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 prefix lines by the number of occurrences<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -d, –repeated
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 only print duplicate lines<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -D, –all-repeated
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print all duplicate lines<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f, –skip-fields=N
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 avoid comparing the first N fields<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -i, –ignore-case
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ignore differences in case when comparing<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s, –skip-chars=N
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 avoid comparing the first N characters<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u, –unique
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 only print unique lines<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -w, –check-chars=N
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 compare no more than N characters in lines<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -N\u00a0\u00a0\u00a0\u00a0\u00a0 same as -f N<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +N\u00a0\u00a0\u00a0\u00a0\u00a0 same as -s N<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0 display the help and exit<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0For more info on this command do: man uniq<\/p>\n

——————————————————————————-<\/p>\n

unset
\n\u00a0this command will remove an alias or function.
\n\u00a0It has the following options:<\/p>\n

\u00a0-v unset a variable only.
\n\u00a0-f unset a function only.<\/p>\n

\u00a0By default unset will first try to unset as a variable and if that
\n\u00a0fails it will try to unset as a function.<\/p>\n

\u00a0Here’s an example:<\/p>\n

\u00a0alien:~$ foo=bar
\n\u00a0alien:~$ echo $foo
\n\u00a0bar
\n\u00a0alien:~$ unset foo
\n\u00a0alien:~$ echo $foo<\/p>\n

\u00a0alien:~$<\/p>\n

\u00a0For more info, do: help unset<\/p>\n

——————————————————————————-<\/p>\n

unzip
\n\u00a0unzip is the tool or command to unzip files, it works like this:
\n\u00a0unzip [arguments] <file.zip><\/p>\n

\u00a0unzip has some arguments I never used, do: unzip –help
\n\u00a0to get a list of valid arguments.
\n\u00a0Also feel free to do: man unzip<\/p>\n

——————————————————————————-<\/p>\n

updatedb
\n\u00a0update the locate database, updatedb works like this:
\n\u00a0updatedb [arguments] <pattern>
\n\u00a0By default updatedb updates the locate database so it covers the
\n\u00a0whole system and all it’s files, but has the following arguments:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u\u00a0\u00a0\u00a0\u00a0\u00a0 Create slocate database starting at the root direc-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 tory.\u00a0 This is the default behavior when called\u00a0 as updatedb.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -U path
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Create slocate database starting at path path.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -e dirs
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Exclude\u00a0 directories\u00a0 in\u00a0 the\u00a0 comma-separated list
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 dirs from the slocate database.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f fstypes
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Exclude file systems in\u00a0 the\u00a0 comma-separated\u00a0 list
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 dirs from the slocate database.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -l <num>
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Security\u00a0 level.\u00a0\u00a0 -l\u00a0 0 turns security checks off,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 which will make searches faster.\u00a0 -l 1 turns\u00a0 security
\n\u00a0 checks on. This is the default.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -q\u00a0\u00a0\u00a0\u00a0\u00a0 Quiet mode; error messages are suppressed.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -v\u00a0\u00a0\u00a0\u00a0\u00a0 Verbose\u00a0 mode;\u00a0 display files indexed when creating database<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help
\n\u00a0 Print a summary of the options to slocate and exit.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Print the version number of slocate and exit.<\/p>\n

\u00a0If you have the whole system updataded in the locate databse,
\n\u00a0to find a file all you have to do is to: locate <file><\/p>\n

\u00a0For more info: man updatedb<\/p>\n

——————————————————————————-<\/p>\n

uptime
\n\u00a0displays the current uptime (the time the system has been on).
\n\u00a0with the load average.
\n\u00a0It shows from left to right:
\n\u00a0The current time, how long the system has been running,
\n\u00a0how many users are currently logged on, and the system load
\n\u00a0averages for the past 1, 5, and 15 minutes.<\/p>\n

\u00a0Also do: man uptime<\/p>\n

——————————————————————————-<\/p>\n

useradd
\n\u00a0useradd adds a user account to the system.
\n\u00a0useradd works like this: useradd [arguments] user<\/p>\n

\u00a0Here’s a cut & paste from it’s manual page (as usual).<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -c comment
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The new user’s password file comment field.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -d home_dir
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The\u00a0 new user will be created using home_dir as the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 value for the user’s login directory.\u00a0 The\u00a0 default
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is to append the login name to default_home and use
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 that as the login directory name.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -e expire_date
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The date on which the user\u00a0 account\u00a0 will\u00a0 be\u00a0 dis-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 abled.\u00a0\u00a0 The\u00a0 date is specified in the format YYYY-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MM-DD.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f inactive_days
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The number of days after a password\u00a0 expires\u00a0 until
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the\u00a0 account is permanently disabled.\u00a0 A value of 0
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 disables the account as soon as\u00a0 the\u00a0 password\u00a0 has
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 expired,\u00a0 and\u00a0 a\u00a0 value of -1 disables the feature.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The default value is -1.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -g initial_group
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The group name or\u00a0 number\u00a0 of\u00a0 the\u00a0 user’s\u00a0 initial
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 login\u00a0 group.\u00a0\u00a0 The group name must exist.\u00a0 A group
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 number must refer to\u00a0 an\u00a0 already\u00a0 existing\u00a0 group.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The default group number is 1.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -G group,[…]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0 list\u00a0 of\u00a0 supplementary groups which the user is
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 also a member of.\u00a0 Each group is separated from the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 next\u00a0 by\u00a0 a\u00a0 comma, with no intervening whitespace.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The groups are subject to the same restrictions\u00a0 as
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the group given with the -g option.\u00a0 The default is
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 for the user to belong only to the initial group.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -m\u00a0\u00a0\u00a0\u00a0\u00a0 The user’s home directory will\u00a0 be\u00a0 created\u00a0 if\u00a0 it
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 does\u00a0 not\u00a0 exist.\u00a0\u00a0 The\u00a0 files\u00a0 contained in skele-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ton_dir will be copied to the home directory if the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -k option is used, otherwise the files contained in
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/etc\/skel will be used\u00a0 instead.\u00a0\u00a0 Any\u00a0 directories
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 contained in skeleton_dir or \/etc\/skel will be cre-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ated in the user’s home directory as well.\u00a0 The\u00a0 -k
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 option\u00a0 is\u00a0 only\u00a0 valid\u00a0 in conjunction with the -m
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 option.\u00a0 The default is to not create the directory
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 and to not copy any files.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -M\u00a0\u00a0\u00a0\u00a0\u00a0 The\u00a0 user\u00a0 home directory will not be created, even
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 if the system wide settings from \/etc\/login.defs is
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to create home dirs.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -n\u00a0\u00a0\u00a0\u00a0\u00a0 A\u00a0 group\u00a0 having\u00a0 the\u00a0 same\u00a0 name as the user being
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 added to the system will\u00a0 be\u00a0 created\u00a0 by\u00a0 default.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 This\u00a0 option\u00a0 will turn off this Red Hat Linux spe-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 cific behavior.
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -r\u00a0\u00a0\u00a0\u00a0\u00a0 This flag is used to create a system account.\u00a0 That
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is, an user with an UID lower than value of UID_MIN
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 defined in \/etc\/login.defs. Note that useradd\u00a0 will
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 not\u00a0 create\u00a0 a\u00a0 home\u00a0 directory\u00a0 for\u00a0 such an user,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 regardless\u00a0\u00a0\u00a0 of\u00a0\u00a0\u00a0 the\u00a0\u00a0\u00a0 default\u00a0\u00a0\u00a0 setting\u00a0\u00a0\u00a0 in
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/etc\/login.defs.\u00a0\u00a0 You have to specify -m option if
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 you want a home directory for a system\u00a0 account\u00a0 to
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 be created.\u00a0 This is an option added by Red Hat.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -p passwd
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The\u00a0 encrypted\u00a0 password,\u00a0 as returned by crypt(3).
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The default is to disable the account.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s shell
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The name of the user’s login shell.\u00a0 The default is
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to\u00a0 leave this field blank, which causes the system
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to select the default login shell.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -u uid\u00a0 The numerical value of the user’s ID.\u00a0\u00a0 This\u00a0 value
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 must\u00a0 be unique, unless the -o option is used.\u00a0 The
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 value must be non-negative.\u00a0 The default is to\u00a0 use
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the\u00a0 smallest\u00a0 ID value greater than 99 and greater
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 than every other user.\u00a0 Values between 0 and 99 are
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 typically reserved for system accounts.<\/p>\n

\u00a0When the -D argument is used useradd with either give the
\n\u00a0default values or update them if there is more arguments.
\n\u00a0The other arguments can be:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -b default_home
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The\u00a0 initial\u00a0 path\u00a0 prefix\u00a0 for\u00a0 a\u00a0 new user’s home
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 directory.\u00a0 The user’s name will be affixed to\u00a0 the
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 end\u00a0 of\u00a0 default_home\u00a0 to\u00a0 create the new directory
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 name if the -d option is not used when\u00a0 creating\u00a0 a
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 new account.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -e default_expire_date
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The date on which the user account is disabled.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -f default_inactive
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The\u00a0 number\u00a0 of\u00a0 days\u00a0 after a password has expired
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 before the account will be disabled.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -g default_group
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The group name or\u00a0 ID\u00a0 for\u00a0 a\u00a0 new\u00a0 user’s\u00a0 initial
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 group.\u00a0 The named group must exist, and a numerical
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 group ID must have an existing entry .<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -s default_shell
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The name of the new user’s login shell.\u00a0 The\u00a0 named
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 program\u00a0 will\u00a0 be\u00a0 used\u00a0 for\u00a0 all\u00a0 future\u00a0 new user
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 accounts.<\/p>\n

\u00a0Also feel free to read the manual page: man useradd<\/p>\n

——————————————————————————-<\/p>\n

userdel
\n\u00a0userdel removes a user from the system.
\n\u00a0userdel works like this: userdel [argument] <user>
\n\u00a0The only argument to this command is:
\n\u00a0-r removes the users home directory, along with the user.<\/p>\n

\u00a0This will delete the users login and everything from the system.<\/p>\n

\u00a0userdel will not remove the user if he is currently logged
\n\u00a0in to the system or have any processes running.
\n\u00a0So make sure you kill all processes owned by the user,
\n\u00a0if any, before removing his\/her account.<\/p>\n

\u00a0To kill the all running processes owned by the same user
\n\u00a0you can do the following command (change <user> to the username):<\/p>\n

\u00a0for pids in `ps U <user> | cut -c 1-6`; do kill -9 $pids ; done<\/p>\n

——————————————————————————-<\/p>\n

users
\n\u00a0Display the currently logged in users.<\/p>\n

——————————————————————————-<\/p>\n

usleep
\n\u00a0usleep is another version of the sleep command, but instead of beeing
\n\u00a0told how many seconds to sleep, it sleeps in microseconds.
\n\u00a0So `usleep 1000000` makes it sleep for 1 second.<\/p>\n

——————————————————————————-<\/p>\n

w
\n\u00a0w is like a mix of who and finger, it’s used to see who’s logged
\n\u00a0on to the system and will show the following:
\n\u00a0login name, terminal, host, login time, idle time, JCPU (total cpu time
\n\u00a0that user (terminal) takes up), PCPU (cpu time of the users current
\n\u00a0process which is shown in the next field), what (process)<\/p>\n

——————————————————————————-<\/p>\n

wall
\n\u00a0wall is a superuser command to send a string of text to all
\n\u00a0consoles\/terminals, wall can work either like: wall <string>
\n\u00a0or: wall <file with string in it>
\n\u00a0To wall special characters like “=)” you need to do it like
\n\u00a0this: wall ‘<string> =)’<\/p>\n

——————————————————————————-<\/p>\n

wc
\n\u00a0word count, works basicly like this: wc [argument] <file>
\n\u00a0Where the arguments can be any of the following:<\/p>\n

\u00a0-c, –bytes, –chars\u00a0\u00a0 print the byte counts
\n\u00a0\u00a0 -l, –lines\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print the newline counts
\n\u00a0\u00a0 -L, –max-line-length\u00a0 print the length of the longest line
\n\u00a0\u00a0 -w, –words\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print the word counts
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –help\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –version\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0So to find out the number of words in a file called say “file1”,
\n\u00a0you would do: wc -w file1
\n\u00a0Or to find out the number of lines in the same file you would
\n\u00a0do: wc -l file1<\/p>\n

\u00a0This little tool can prove to be very useful, though when you
\n\u00a0use it with the -l\/–lines argument it will only count lines that
\n\u00a0contains any characters, if you wanna count all lines
\n\u00a0including empty lines, use: grep -c . file1
\n\u00a0or the same thing in another way: cat file1 | grep -c .<\/p>\n

——————————————————————————-<\/p>\n

whatis
\n\u00a0whatis searches for words in the whatis database, say that you
\n\u00a0are looking for a manual page about the `shutdown` command.
\n\u00a0Then you can do: whatis shutdown
\n\u00a0for more information, do: man whatis
\n\u00a0Or: man apropos<\/p>\n

——————————————————————————-<\/p>\n

whereis
\n\u00a0whereis looks for something just as the `which` command here below.
\n\u00a0but looks for matches in more places, as the manual page directory’s.
\n\u00a0It works like this: whereis [argument] <what-you-wanna-find>
\n\u00a0Try this command a few times, and if you want to learn
\n\u00a0more about it as it’s arguments and so do: man whereis<\/p>\n

——————————————————————————-<\/p>\n

which
\n\u00a0which will tell you where a command is located, as if you
\n\u00a0do: which shutdown
\n\u00a0it will answer: \/sbin\/shutdown
\n\u00a0This command will search your path for whatever you type after it.
\n\u00a0This command is best used in scripts and functions, like this:<\/p>\n

\u00a0function whichrpm { rpm -qf `which $1`; }<\/p>\n

\u00a0The which command has some arguments, and more examples in it’s
\n\u00a0manual page, so for more info do: man which<\/p>\n

——————————————————————————-<\/p>\n

who
\n\u00a0who is a little command that shows you who’s logged on,
\n\u00a0on what tty and at what time they logged on.
\n\u00a0I never ever used this command with any arguments,
\n\u00a0but if you want to learn more about this command do: who –help
\n\u00a0or: man who<\/p>\n

——————————————————————————-<\/p>\n

whoami
\n\u00a0displays your user name, same as `id -un`.
\n\u00a0whoami can be used with the following arguments:
\n\u00a0–help\u00a0\u00a0\u00a0\u00a0\u00a0 display this help and exit
\n\u00a0\u00a0 –version\u00a0\u00a0 output version information and exit<\/p>\n

\u00a0Not much more to say about this command.<\/p>\n

——————————————————————————-<\/p>\n

whois
\n\u00a0whois is a tool that asks internic for information on a domain name.
\n\u00a0This is only for .com .org .net etc.
\n\u00a0If any luck it will give you the name and other info of the one that
\n\u00a0registered the domain, and it’s name servers.<\/p>\n

\u00a0whois can also be used to do: whois user@host<\/a><\/p>\n

\u00a0For more info on this command do: man whois
\n\u00a0Or: man fwhois<\/p>\n

——————————————————————————-<\/p>\n

yes
\n\u00a0yes is a command that repeats the same thing over and over again,
\n\u00a0it’s used as this: yes <string>
\n\u00a0If no string or word is supplied it will repeat the character ‘y’.
\n\u00a0yes can be used with the following arguments:<\/p>\n

\u00a0–version display the version and exit.
\n\u00a0–help\u00a0 display the help and exit.<\/p>\n

——————————————————————————-<\/p>\n

zip
\n\u00a0zip is a compression tool, to compress with zip do:<\/p>\n

\u00a0zip [arguments] <file.zip> <file1> <file2> etc.<\/p>\n

\u00a0The arguments can be the following:<\/p>\n

\u00a0-f\u00a0\u00a0 freshen: only changed files
\n\u00a0-u\u00a0\u00a0 update: only changed or new files
\n\u00a0\u00a0 -d\u00a0\u00a0 delete entries in zipfile
\n\u00a0-m\u00a0\u00a0 move into zipfile (delete files)
\n\u00a0\u00a0 -r\u00a0\u00a0 recurse into directories
\n\u00a0-j\u00a0\u00a0 junk (don’t record) directory names
\n\u00a0\u00a0 -0\u00a0\u00a0 store only
\n\u00a0-l\u00a0\u00a0 convert LF to CR LF (-ll CR LF to LF)
\n\u00a0\u00a0 -1\u00a0\u00a0 compress faster
\n\u00a0-9\u00a0\u00a0 compress better
\n\u00a0\u00a0 -q\u00a0\u00a0 quiet operation
\n\u00a0-v\u00a0\u00a0 verbose operation\/print version info
\n\u00a0\u00a0 -c\u00a0\u00a0 add one-line comments
\n\u00a0-z\u00a0\u00a0 add zipfile comment
\n\u00a0\u00a0 -@\u00a0\u00a0 read names from stdin
\n\u00a0-o\u00a0\u00a0 make zipfile as old as latest entry
\n\u00a0\u00a0 -x\u00a0\u00a0 exclude the following names
\n\u00a0-i\u00a0\u00a0 include only the following names
\n\u00a0\u00a0 -F\u00a0\u00a0 fix zipfile (-FF try harder)
\n\u00a0-D\u00a0\u00a0 do not add directory entries
\n\u00a0\u00a0 -A\u00a0\u00a0 adjust self-extracting exe
\n\u00a0-J\u00a0\u00a0 junk zipfile prefix (unzipsfx)
\n\u00a0\u00a0 -T\u00a0\u00a0 test zipfile integrity
\n\u00a0-X\u00a0\u00a0 eXclude eXtra file attributes
\n\u00a0\u00a0 -y\u00a0\u00a0 store symbolic links as the link instead of the referenced file
\n\u00a0\u00a0 -R\u00a0\u00a0 PKZIP recursion (see manual)
\n\u00a0\u00a0 -h\u00a0\u00a0 show the help
\n\u00a0-n\u00a0\u00a0 don’t compress these suffixes<\/p>\n

\u00a0To uncompress a zip file, use the `unzip` command.<\/p>\n

——————————————————————————-<\/p>\n

And that is most of the commands you’ll ever encounter while scripting or
\nusing a *nix system.
\nThere are LOADS of other commands, but not many that are as used as these
\nI just explained.<\/p>\n

There are more really useful commands that I never seen as default
\non any system aswell, like pgp and gpg, I havent included those since
\nthere full documentation comes with the same package as that
\ncommand\/application if you download it.<\/p>\n

So, as I said these are the most useful commands, but if someone out there
\nthink I missed some really useful command send me a mail and I’ll add it.<\/p>\n

===============================================================================
\n10 – Other Frequently asked questions with answers.
\n===============================================================================<\/p>\n

Q: How can I play an .au file ?
\nA: The file suffix .au means it’s an audio file, so you can either do
\n\u00a0\u00a0 the same as for mp3’s: mpg123 file.au
\n\u00a0\u00a0 or you can (since .au files are raw audio): cat file.au > \/dev\/dsp
\n\u00a0\u00a0 or: cat file.au > \/dev\/audio<\/p>\n

Q: What exactly is bash ?
\nA: If you have read this tutorial you would know … it’s a shell type.<\/p>\n

Q: I wanna make some sub-directory’s to \/usr\/local\/ but I’m to lazy to write
\n\u00a0\u00a0 almost the same line over and over again, is there any easier way ?
\nA: Yes there is: mkdir \/usr\/local\/{dir1,dir2,dir3}<\/p>\n

Q: I have a dir with files like this: file.1 file.2 file.3 etc.
\n\u00a0\u00a0 is there any way I can list say, file.3, file.4, file.6, file.9 only
\n\u00a0\u00a0 without using grep ?
\nA: Yes there is: ls file*[3469]*<\/p>\n

Q: I want to remove some files with wildcards included in the command
\n\u00a0\u00a0 (rm -rf .??*), is there any way I can see what the command will remove
\n\u00a0\u00a0 before I actually do the command ?
\nA: Yes there is: echo rm -rf .??*<\/p>\n

Q: How can I remove file names that are\/have special characters like a file
\n\u00a0\u00a0 named:\u00a0 -!?* !!?
\nA: Do this: rm .\/-\\!\\?\\*\\ \\!\\!\\?
\n\u00a0\u00a0 The .\/ makes sure it will look in the current directory, and the \\
\n\u00a0\u00a0 (back slashes) will make sure that the special characters special meaning
\n\u00a0\u00a0 is over looked, so they are treated just like any other character.<\/p>\n

Q: I accidently deleted something on my system, is there any way
\n\u00a0\u00a0 of getting it back ?
\nA: Yes there is, read this file \/usr\/doc\/HOWTO\/mini\/Ext2fs-Undeletion
\n\u00a0\u00a0 (or \/usr\/doc\/HOWTO\/mini\/Ext2fs-Undeletion.gz)
\n\u00a0\u00a0 This is also good knowledge if someone *hacks* your system
\n\u00a0\u00a0 and think they are safe just because they deleted the logs.
\n\u00a0\u00a0 Or you can download a program called ‘recover’ from www.freshmeat.net<\/a><\/p>\n

Q: How do I compile my kernel ?
\nA: Read this file:\u00a0 \/usr\/doc\/HOWTO\/Kernel-HOWTO<\/p>\n

Q: Can I make a variable read-only so noone can change it ?
\nA: Yes you can: readonly variable_name
\n\u00a0\u00a0 As say that I have a variable: $myvar
\n\u00a0\u00a0 Then I would do: readonly myvar
\n\u00a0\u00a0 And to display all the read-only variables just do: readonly<\/p>\n

Q: How can I display all the set variables ?
\nA: With the command: set
\n\u00a0\u00a0 To get the eviorment use this command: env
\n\u00a0\u00a0 And to display the system variables, type a $ and press TAB.<\/p>\n

Q: Something is wrong with a script, but I dont know what, how can I find out ?
\nA: by doing this: \/bin\/sh -x <scriptname>
\n\u00a0\u00a0 + means that the command was successful.
\n\u00a0\u00a0 – means that the command was unsuccessful.<\/p>\n

Q: I’m using hexedit and simlar commands alot, but I’m getting to lazy to
\n\u00a0\u00a0 find out where all the binarys live, isn’t there any faster way of
\n\u00a0\u00a0 opening a binary or script that’s in my $PATH then to locate, find or
\n\u00a0\u00a0 something like that and then go from there ?
\nA: Well, I dont know how much faster it is, but you can always
\n\u00a0\u00a0 do this: hexedit `which <file>`<\/p>\n

Q: How can I list only the directorys in a directory without the files ?
\nA: Well, some distros has an alias “lsd”, and it does: ls -d *\/<\/p>\n

Q: How can I transfer a file if the computer doesn’t have any FTP ?
\nA: If you wanna actually copy a file to a place that dont have ftp
\n\u00a0\u00a0 or for some other reason you can’t use ftp, there is 2 commands that can
\n\u00a0\u00a0 do this: scp (secure copy – requiers ssh)
\n\u00a0\u00a0 And: rcp (remote copy – requiers rlogin)
\n\u00a0\u00a0 They work like this:
\n\u00a0\u00a0 scp local.file user@host.domain.com:\/remote\/directory\/<\/a>
\n\u00a0\u00a0 rcp local.file user@host.domain.com:\/remote\/directory\/<\/a><\/p>\n

Q: Is there any way I can view my processes so I can see the free stack,
\n\u00a0\u00a0 father processes siblings and children etc. ?
\nA: Yes there is, press: Ctrl + Scroll-Lock<\/p>\n

Q: Is there any way I can view the memory buffers etc. ?
\nA: Yes there is, press: Shift + Scroll-Lock<\/p>\n

Q: Is there any way to get some info from the stack ?
\nA: Yes there is press: AltGr + Scroll-Lock<\/p>\n

Q: My volume is really low when I play stuff, how can I change it ?
\nA: Use the program `aumix` it should be on most systems by default,
\n\u00a0\u00a0 and it’s pretty self explanatory.<\/p>\n

Q: I think it’s a pain pressing upp arrow until I reach the command I want
\n\u00a0\u00a0 to use, that is to long to type again, is there any faster way ?
\nA: Yes, press Ctrl+R and type something that matches a previously used
\n\u00a0\u00a0 command, and just press enter to execute it or Ctrl+C to cancel.<\/p>\n

Q: Is there any console based mpeg movie players ?
\nA: Not that I know of, but if there is, I’d like to know myself.<\/p>\n

Q: How can I take a screenshot without having to install Gimp or something
\n\u00a0\u00a0 like that ?
\nA: Well, the easyest way of taking a screen shot in X is to do the
\n\u00a0\u00a0 following command: import -window root foo.jpg
\n\u00a0\u00a0 That will dump a screen shot as foo.jpg, in your current directory.<\/p>\n

Q: How can I import variables from one script to another, like a config file ?
\nA: You can read all variables from a file by doing “. <file name>”, say
\n\u00a0\u00a0 that you have a file called myvars and you want to you those variables
\n\u00a0\u00a0 in a script, then you add the line:\u00a0 . myvars
\n\u00a0\u00a0 in the beginning of the script, after the #!\/bin\/bash line.
\n\u00a0\u00a0 The . is actually a command, that reads and executes commands in a file,
\n\u00a0\u00a0 which here works to imported the variables since they are executed
\n\u00a0\u00a0 from within the script.<\/p>\n

Q: I’m using `port sentry` as a firewall controll software, now my routing
\n\u00a0\u00a0 table is over full, how can I take away all that’s routed to ‘localhost’
\n\u00a0\u00a0 in one command or string ?
\nA: Well like this: for ips in `route | grep local | cut -c 1-14`; do route del -host $ips gw 127.0.0.1 2>\/dev\/null ; done
\n\u00a0\u00a0 That should do the trick.<\/p>\n

Q: If I’m in a directory full or rpm files and I wanna find out which rpm that
\n\u00a0\u00a0 contain say the file vga.h, how would I do that ?
\nA: Well you can do this:
\n\u00a0\u00a0 for foo in `ls -1 *.rpm`; do rpm -qlp $foo | grep vga.h 1>\/dev\/null 2>&1 && echo $foo; done<\/p>\n

Q: Is there any place I can find out where all the ^ (Ctrl) characters mean ?
\nA: Yes, look in the ascii table below, it works like this:
\n\u00a0\u00a0 M is the 13’th character in the alphabet, and in the ascii table
\n\u00a0\u00a0 013 (dec) has the value CR which means Carriage Return.
\n\u00a0\u00a0 this means that ^M (Ctrl+M) is the same as pressing the return button.
\n\u00a0\u00a0 And ^A which is 001 (dec) is Start of Header, in other words take the
\n\u00a0\u00a0 cursor to the beginning of the current line.<\/p>\n

Q: How do I write stuff in hex code ?
\nA: Well, like this:<\/p>\n

——————————————————————————-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ASCII codes
\n——————————————————————————-<\/p>\n

\u00a0\u00a0\u00a0 ASCII Table (7-bit)<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Decimal\u00a0\u00a0 Octal\u00a0\u00a0 Hex\u00a0\u00a0\u00a0 Binary\u00a0\u00a0\u00a0\u00a0 Value
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ——-\u00a0\u00a0 —–\u00a0\u00a0 —\u00a0\u00a0\u00a0 ——\u00a0\u00a0\u00a0\u00a0 —–
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 000\u00a0\u00a0\u00a0\u00a0\u00a0 000\u00a0\u00a0\u00a0 000\u00a0\u00a0 00000000\u00a0\u00a0\u00a0\u00a0\u00a0 NUL\u00a0\u00a0\u00a0 (Null char.)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 001\u00a0\u00a0\u00a0\u00a0\u00a0 001\u00a0\u00a0\u00a0 001\u00a0\u00a0 00000001\u00a0\u00a0\u00a0\u00a0\u00a0 SOH\u00a0\u00a0\u00a0 (Start of Header)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 002\u00a0\u00a0\u00a0\u00a0\u00a0 002\u00a0\u00a0\u00a0 002\u00a0\u00a0 00000010\u00a0\u00a0\u00a0\u00a0\u00a0 STX\u00a0\u00a0\u00a0 (Start of Text)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 003\u00a0\u00a0\u00a0\u00a0\u00a0 003\u00a0\u00a0\u00a0 003\u00a0\u00a0 00000011\u00a0\u00a0\u00a0\u00a0\u00a0 ETX\u00a0\u00a0\u00a0 (End of Text)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 004\u00a0\u00a0\u00a0\u00a0\u00a0 004\u00a0\u00a0\u00a0 004\u00a0\u00a0 00000100\u00a0\u00a0\u00a0\u00a0\u00a0 EOT\u00a0\u00a0\u00a0 (End of Transmission)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 005\u00a0\u00a0\u00a0\u00a0\u00a0 005\u00a0\u00a0\u00a0 005\u00a0\u00a0 00000101\u00a0\u00a0\u00a0\u00a0\u00a0 ENQ\u00a0\u00a0\u00a0 (Enquiry)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 006\u00a0\u00a0\u00a0\u00a0\u00a0 006\u00a0\u00a0\u00a0 006\u00a0\u00a0 00000110\u00a0\u00a0\u00a0\u00a0\u00a0 ACK\u00a0\u00a0\u00a0 (Acknowledgment)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 007\u00a0\u00a0\u00a0\u00a0\u00a0 007\u00a0\u00a0\u00a0 007\u00a0\u00a0 00000111\u00a0\u00a0\u00a0\u00a0\u00a0 BEL\u00a0\u00a0\u00a0 (Bell)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 008\u00a0\u00a0\u00a0\u00a0\u00a0 010\u00a0\u00a0\u00a0 008\u00a0\u00a0 00001000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 BS\u00a0\u00a0\u00a0 (Backspace)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 009\u00a0\u00a0\u00a0\u00a0\u00a0 011\u00a0\u00a0\u00a0 009\u00a0\u00a0 00001001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 HT\u00a0\u00a0\u00a0 (Horizontal Tab)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 010\u00a0\u00a0\u00a0\u00a0\u00a0 012\u00a0\u00a0\u00a0 00A\u00a0\u00a0 00001010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 LF\u00a0\u00a0\u00a0 (Line Feed)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 011\u00a0\u00a0\u00a0\u00a0\u00a0 013\u00a0\u00a0\u00a0 00B\u00a0\u00a0 00001011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 VT\u00a0\u00a0\u00a0 (Vertical Tab)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 012\u00a0\u00a0\u00a0\u00a0\u00a0 014\u00a0\u00a0\u00a0 00C\u00a0\u00a0 00001100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 FF\u00a0\u00a0\u00a0 (Form Feed)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 013\u00a0\u00a0\u00a0\u00a0\u00a0 015\u00a0\u00a0\u00a0 00D\u00a0\u00a0 00001101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 CR\u00a0\u00a0\u00a0 (Carriage Return)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 014\u00a0\u00a0\u00a0\u00a0\u00a0 016\u00a0\u00a0\u00a0 00E\u00a0\u00a0 00001110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SO\u00a0\u00a0\u00a0 (Serial In)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 015\u00a0\u00a0\u00a0\u00a0\u00a0 017\u00a0\u00a0\u00a0 00F\u00a0\u00a0 00001111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SI\u00a0\u00a0\u00a0 (Serial Out)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 016\u00a0\u00a0\u00a0\u00a0\u00a0 020\u00a0\u00a0\u00a0 010\u00a0\u00a0 00010000\u00a0\u00a0\u00a0\u00a0\u00a0 DLE\u00a0\u00a0\u00a0 (Data Link Escape)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 017\u00a0\u00a0\u00a0\u00a0\u00a0 021\u00a0\u00a0\u00a0 011\u00a0\u00a0 00010001\u00a0\u00a0\u00a0\u00a0\u00a0 DC1 (XON) (Device Control 1)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 018\u00a0\u00a0\u00a0\u00a0\u00a0 022\u00a0\u00a0\u00a0 012\u00a0\u00a0 00010010\u00a0\u00a0\u00a0\u00a0\u00a0 DC2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (Device Control 2)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 019\u00a0\u00a0\u00a0\u00a0\u00a0 023\u00a0\u00a0\u00a0 013\u00a0\u00a0 00010011\u00a0\u00a0\u00a0\u00a0\u00a0 DC3 (XOFF)(Device Control 3)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 020\u00a0\u00a0\u00a0\u00a0\u00a0 024\u00a0\u00a0\u00a0 014\u00a0\u00a0 00010100\u00a0\u00a0\u00a0\u00a0\u00a0 DC4\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (Device Control 4)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 021\u00a0\u00a0\u00a0\u00a0\u00a0 025\u00a0\u00a0\u00a0 015\u00a0\u00a0 00010101\u00a0\u00a0\u00a0\u00a0\u00a0 NAK\u00a0\u00a0\u00a0 (Negative Acknowledgement)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 022\u00a0\u00a0\u00a0\u00a0\u00a0 026\u00a0\u00a0\u00a0 016\u00a0\u00a0 00010110\u00a0\u00a0\u00a0\u00a0\u00a0 SYN\u00a0\u00a0\u00a0 (Synchronous Idle)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 023\u00a0\u00a0\u00a0\u00a0\u00a0 027\u00a0\u00a0\u00a0 017\u00a0\u00a0 00010111\u00a0\u00a0\u00a0\u00a0\u00a0 ETB\u00a0\u00a0\u00a0 (End of Trans. Block)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 024\u00a0\u00a0\u00a0\u00a0\u00a0 030\u00a0\u00a0\u00a0 018\u00a0\u00a0 00011000\u00a0\u00a0\u00a0\u00a0\u00a0 CAN\u00a0\u00a0\u00a0 (Cancel)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 025\u00a0\u00a0\u00a0\u00a0\u00a0 031\u00a0\u00a0\u00a0 019\u00a0\u00a0 00011001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 EM
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 026\u00a0\u00a0\u00a0\u00a0\u00a0 032\u00a0\u00a0\u00a0 01A\u00a0\u00a0 00011010\u00a0\u00a0\u00a0\u00a0\u00a0 SUB
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 027\u00a0\u00a0\u00a0\u00a0\u00a0 033\u00a0\u00a0\u00a0 01B\u00a0\u00a0 00011011\u00a0\u00a0\u00a0\u00a0\u00a0 ESC\u00a0\u00a0\u00a0 (Escape)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 028\u00a0\u00a0\u00a0\u00a0\u00a0 034\u00a0\u00a0\u00a0 01C\u00a0\u00a0 00011100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 FS\u00a0\u00a0\u00a0 (File Separator)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 029\u00a0\u00a0\u00a0\u00a0\u00a0 035\u00a0\u00a0\u00a0 01D\u00a0\u00a0 00011101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 GS
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 030\u00a0\u00a0\u00a0\u00a0\u00a0 036\u00a0\u00a0\u00a0 01E\u00a0\u00a0 00011110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 RS\u00a0\u00a0\u00a0 (Request to Send)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 031\u00a0\u00a0\u00a0\u00a0\u00a0 037\u00a0\u00a0\u00a0 01F\u00a0\u00a0 00011111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 US
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 032\u00a0\u00a0\u00a0\u00a0\u00a0 040\u00a0\u00a0\u00a0 020\u00a0\u00a0 00100000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SP\u00a0\u00a0\u00a0 (Space)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 033\u00a0\u00a0\u00a0\u00a0\u00a0 041\u00a0\u00a0\u00a0 021\u00a0\u00a0 00100001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 !
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 034\u00a0\u00a0\u00a0\u00a0\u00a0 042\u00a0\u00a0\u00a0 022\u00a0\u00a0 00100010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ”
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 035\u00a0\u00a0\u00a0\u00a0\u00a0 043\u00a0\u00a0\u00a0 023\u00a0\u00a0 00100011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 #
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 036\u00a0\u00a0\u00a0\u00a0\u00a0 044\u00a0\u00a0\u00a0 024\u00a0\u00a0 00100100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 $
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 037\u00a0\u00a0\u00a0\u00a0\u00a0 045\u00a0\u00a0\u00a0 025\u00a0\u00a0 00100101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 %
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 038\u00a0\u00a0\u00a0\u00a0\u00a0 046\u00a0\u00a0\u00a0 026\u00a0\u00a0 00100110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 &
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 039\u00a0\u00a0\u00a0\u00a0\u00a0 047\u00a0\u00a0\u00a0 027\u00a0\u00a0 00100111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ‘
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 040\u00a0\u00a0\u00a0\u00a0\u00a0 050\u00a0\u00a0\u00a0 028\u00a0\u00a0 00101000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 041\u00a0\u00a0\u00a0\u00a0\u00a0 051\u00a0\u00a0\u00a0 029\u00a0\u00a0 00101001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 )
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 042\u00a0\u00a0\u00a0\u00a0\u00a0 052\u00a0\u00a0\u00a0 02A\u00a0\u00a0 00101010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 *
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 043\u00a0\u00a0\u00a0\u00a0\u00a0 053\u00a0\u00a0\u00a0 02B\u00a0\u00a0 00101011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 044\u00a0\u00a0\u00a0\u00a0\u00a0 054\u00a0\u00a0\u00a0 02C\u00a0\u00a0 00101100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 045\u00a0\u00a0\u00a0\u00a0\u00a0 055\u00a0\u00a0\u00a0 02D\u00a0\u00a0 00101101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 –
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 046\u00a0\u00a0\u00a0\u00a0\u00a0 056\u00a0\u00a0\u00a0 02E\u00a0\u00a0 00101110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 047\u00a0\u00a0\u00a0\u00a0\u00a0 057\u00a0\u00a0\u00a0 02F\u00a0\u00a0 00101111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 048\u00a0\u00a0\u00a0\u00a0\u00a0 060\u00a0\u00a0\u00a0 030\u00a0\u00a0 00110000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 049\u00a0\u00a0\u00a0\u00a0\u00a0 061\u00a0\u00a0\u00a0 031\u00a0\u00a0 00110001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 050\u00a0\u00a0\u00a0\u00a0\u00a0 062\u00a0\u00a0\u00a0 032\u00a0\u00a0 00110010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 051\u00a0\u00a0\u00a0\u00a0\u00a0 063\u00a0\u00a0\u00a0 033\u00a0\u00a0 00110011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 052\u00a0\u00a0\u00a0\u00a0\u00a0 064\u00a0\u00a0\u00a0 034\u00a0\u00a0 00110100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 4
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 053\u00a0\u00a0\u00a0\u00a0\u00a0 065\u00a0\u00a0\u00a0 035\u00a0\u00a0 00110101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 5
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 054\u00a0\u00a0\u00a0\u00a0\u00a0 066\u00a0\u00a0\u00a0 036\u00a0\u00a0 00110110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 6
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 055\u00a0\u00a0\u00a0\u00a0\u00a0 067\u00a0\u00a0\u00a0 037\u00a0\u00a0 00110111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 7
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 056\u00a0\u00a0\u00a0\u00a0\u00a0 070\u00a0\u00a0\u00a0 038\u00a0\u00a0 00111000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 8
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 057\u00a0\u00a0\u00a0\u00a0\u00a0 071\u00a0\u00a0\u00a0 039\u00a0\u00a0 00111001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 9
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 058\u00a0\u00a0\u00a0\u00a0\u00a0 072\u00a0\u00a0\u00a0 03A\u00a0\u00a0 00111010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 :
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 059\u00a0\u00a0\u00a0\u00a0\u00a0 073\u00a0\u00a0\u00a0 03B\u00a0\u00a0 00111011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 060\u00a0\u00a0\u00a0\u00a0\u00a0 074\u00a0\u00a0\u00a0 03C\u00a0\u00a0 00111100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 061\u00a0\u00a0\u00a0\u00a0\u00a0 075\u00a0\u00a0\u00a0 03D\u00a0\u00a0 00111101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 =
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 062\u00a0\u00a0\u00a0\u00a0\u00a0 076\u00a0\u00a0\u00a0 03E\u00a0\u00a0 00111110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 >
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 063\u00a0\u00a0\u00a0\u00a0\u00a0 077\u00a0\u00a0\u00a0 03F\u00a0\u00a0 00111111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ?
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 064\u00a0\u00a0\u00a0\u00a0\u00a0 100\u00a0\u00a0\u00a0 040\u00a0\u00a0 01000000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 @
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 065\u00a0\u00a0\u00a0\u00a0\u00a0 101\u00a0\u00a0\u00a0 041\u00a0\u00a0 01000001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 066\u00a0\u00a0\u00a0\u00a0\u00a0 102\u00a0\u00a0\u00a0 042\u00a0\u00a0 01000010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 B
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 067\u00a0\u00a0\u00a0\u00a0\u00a0 103\u00a0\u00a0\u00a0 043\u00a0\u00a0 01000011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 068\u00a0\u00a0\u00a0\u00a0\u00a0 104\u00a0\u00a0\u00a0 044\u00a0\u00a0 01000100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 D
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 069\u00a0\u00a0\u00a0\u00a0\u00a0 105\u00a0\u00a0\u00a0 045\u00a0\u00a0 01000101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 E
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 070\u00a0\u00a0\u00a0\u00a0\u00a0 106\u00a0\u00a0\u00a0 046\u00a0\u00a0 01000110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 F
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 071\u00a0\u00a0\u00a0\u00a0\u00a0 107\u00a0\u00a0\u00a0 047\u00a0\u00a0 01000111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 G
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 072\u00a0\u00a0\u00a0\u00a0\u00a0 110\u00a0\u00a0\u00a0 048\u00a0\u00a0 01001000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 H
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 073\u00a0\u00a0\u00a0\u00a0\u00a0 111\u00a0\u00a0\u00a0 049\u00a0\u00a0 01001001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 I
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 074\u00a0\u00a0\u00a0\u00a0\u00a0 112\u00a0\u00a0\u00a0 04A\u00a0\u00a0 01001010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 075\u00a0\u00a0\u00a0\u00a0\u00a0 113\u00a0\u00a0\u00a0 04B\u00a0\u00a0 01001011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 K
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 076\u00a0\u00a0\u00a0\u00a0\u00a0 114\u00a0\u00a0\u00a0 04C\u00a0\u00a0 01001100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 L
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 077\u00a0\u00a0\u00a0\u00a0\u00a0 115\u00a0\u00a0\u00a0 04D\u00a0\u00a0 01001101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 M
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 078\u00a0\u00a0\u00a0\u00a0\u00a0 116\u00a0\u00a0\u00a0 04E\u00a0\u00a0 01001110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 N
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 079\u00a0\u00a0\u00a0\u00a0\u00a0 117\u00a0\u00a0\u00a0 04F\u00a0\u00a0 01001111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 O
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 080\u00a0\u00a0\u00a0\u00a0\u00a0 120\u00a0\u00a0\u00a0 050\u00a0\u00a0 01010000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 P
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 081\u00a0\u00a0\u00a0\u00a0\u00a0 121\u00a0\u00a0\u00a0 051\u00a0\u00a0 01010001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Q
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 082\u00a0\u00a0\u00a0\u00a0\u00a0 122\u00a0\u00a0\u00a0 052\u00a0\u00a0 01010010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 R
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 083\u00a0\u00a0\u00a0\u00a0\u00a0 123\u00a0\u00a0\u00a0 053\u00a0\u00a0 01010011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 S
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 084\u00a0\u00a0\u00a0\u00a0\u00a0 124\u00a0\u00a0\u00a0 054\u00a0\u00a0 01010100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 T
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 085\u00a0\u00a0\u00a0\u00a0\u00a0 125\u00a0\u00a0\u00a0 055\u00a0\u00a0 01010101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 U
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 086\u00a0\u00a0\u00a0\u00a0\u00a0 126\u00a0\u00a0\u00a0 056\u00a0\u00a0 01010110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 V
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 087\u00a0\u00a0\u00a0\u00a0\u00a0 127\u00a0\u00a0\u00a0 057\u00a0\u00a0 01011111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 W
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 088\u00a0\u00a0\u00a0\u00a0\u00a0 130\u00a0\u00a0\u00a0 058\u00a0\u00a0 01011000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 X
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 089\u00a0\u00a0\u00a0\u00a0\u00a0 131\u00a0\u00a0\u00a0 059\u00a0\u00a0 01011001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Y
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 090\u00a0\u00a0\u00a0\u00a0\u00a0 132\u00a0\u00a0\u00a0 05A\u00a0\u00a0 01011010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Z
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 091\u00a0\u00a0\u00a0\u00a0\u00a0 133\u00a0\u00a0\u00a0 05B\u00a0\u00a0 01011011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 [
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 092\u00a0\u00a0\u00a0\u00a0\u00a0 134\u00a0\u00a0\u00a0 05C\u00a0\u00a0 01011100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \\
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 093\u00a0\u00a0\u00a0\u00a0\u00a0 135\u00a0\u00a0\u00a0 05D\u00a0\u00a0 01011101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ]
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 094\u00a0\u00a0\u00a0\u00a0\u00a0 136\u00a0\u00a0\u00a0 05E\u00a0\u00a0 01011110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ^
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 095\u00a0\u00a0\u00a0\u00a0\u00a0 137\u00a0\u00a0\u00a0 05F\u00a0\u00a0 01011111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 _
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 096\u00a0\u00a0\u00a0\u00a0\u00a0 140\u00a0\u00a0\u00a0 060\u00a0\u00a0 01100000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 `
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 097\u00a0\u00a0\u00a0\u00a0\u00a0 141\u00a0\u00a0\u00a0 061\u00a0\u00a0 01100001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 a
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 098\u00a0\u00a0\u00a0\u00a0\u00a0 142\u00a0\u00a0\u00a0 062\u00a0\u00a0 01100010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 099\u00a0\u00a0\u00a0\u00a0\u00a0 143\u00a0\u00a0\u00a0 063\u00a0\u00a0 01100011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 100\u00a0\u00a0\u00a0\u00a0\u00a0 144\u00a0\u00a0\u00a0 064\u00a0\u00a0 01100100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 d
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101\u00a0\u00a0\u00a0\u00a0\u00a0 145\u00a0\u00a0\u00a0 065\u00a0\u00a0 01100101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 e
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102\u00a0\u00a0\u00a0\u00a0\u00a0 146\u00a0\u00a0\u00a0 066\u00a0\u00a0 01100110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 f
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 103\u00a0\u00a0\u00a0\u00a0\u00a0 147\u00a0\u00a0\u00a0 067\u00a0\u00a0 01100111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 g
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 104\u00a0\u00a0\u00a0\u00a0\u00a0 150\u00a0\u00a0\u00a0 068\u00a0\u00a0 01101000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 h
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 105\u00a0\u00a0\u00a0\u00a0\u00a0 151\u00a0\u00a0\u00a0 069\u00a0\u00a0 01101001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 i
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 106\u00a0\u00a0\u00a0\u00a0\u00a0 152\u00a0\u00a0\u00a0 06A\u00a0\u00a0 01101010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 j
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 107\u00a0\u00a0\u00a0\u00a0\u00a0 153\u00a0\u00a0\u00a0 06B\u00a0\u00a0 01101011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 k
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 108\u00a0\u00a0\u00a0\u00a0\u00a0 154\u00a0\u00a0\u00a0 06C\u00a0\u00a0 01101100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 l
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 109\u00a0\u00a0\u00a0\u00a0\u00a0 155\u00a0\u00a0\u00a0 06D\u00a0\u00a0 01101101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 m
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 110\u00a0\u00a0\u00a0\u00a0\u00a0 156\u00a0\u00a0\u00a0 06E\u00a0\u00a0 01101110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 111\u00a0\u00a0\u00a0\u00a0\u00a0 157\u00a0\u00a0\u00a0 06F\u00a0\u00a0 01101111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 o
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 112\u00a0\u00a0\u00a0\u00a0\u00a0 160\u00a0\u00a0\u00a0 070\u00a0\u00a0 01110000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 p
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 113\u00a0\u00a0\u00a0\u00a0\u00a0 161\u00a0\u00a0\u00a0 071\u00a0\u00a0 01110001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 q
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 114\u00a0\u00a0\u00a0\u00a0\u00a0 162\u00a0\u00a0\u00a0 072\u00a0\u00a0 01110010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 r
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 115\u00a0\u00a0\u00a0\u00a0\u00a0 163\u00a0\u00a0\u00a0 073\u00a0\u00a0 01110011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 s
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 116\u00a0\u00a0\u00a0\u00a0\u00a0 164\u00a0\u00a0\u00a0 074\u00a0\u00a0 01110100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 t
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 117\u00a0\u00a0\u00a0\u00a0\u00a0 165\u00a0\u00a0\u00a0 075\u00a0\u00a0 01110101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 u
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 118\u00a0\u00a0\u00a0\u00a0\u00a0 166\u00a0\u00a0\u00a0 076\u00a0\u00a0 01110110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 v
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 119\u00a0\u00a0\u00a0\u00a0\u00a0 167\u00a0\u00a0\u00a0 077\u00a0\u00a0 01110111\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 w
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 120\u00a0\u00a0\u00a0\u00a0\u00a0 170\u00a0\u00a0\u00a0 078\u00a0\u00a0 01111000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 x
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 121\u00a0\u00a0\u00a0\u00a0\u00a0 171\u00a0\u00a0\u00a0 079\u00a0\u00a0 01111001\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 y
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 122\u00a0\u00a0\u00a0\u00a0\u00a0 172\u00a0\u00a0\u00a0 07A\u00a0\u00a0 01111010\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 z
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 123\u00a0\u00a0\u00a0\u00a0\u00a0 173\u00a0\u00a0\u00a0 07B\u00a0\u00a0 01111011\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 {
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 124\u00a0\u00a0\u00a0\u00a0\u00a0 174\u00a0\u00a0\u00a0 07C\u00a0\u00a0 01111100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 |
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 125\u00a0\u00a0\u00a0\u00a0\u00a0 175\u00a0\u00a0\u00a0 07D\u00a0\u00a0 01111101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 }
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 126\u00a0\u00a0\u00a0\u00a0\u00a0 176\u00a0\u00a0\u00a0 07E\u00a0\u00a0 01111110\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ~
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 127\u00a0\u00a0\u00a0\u00a0\u00a0 177\u00a0\u00a0\u00a0 07F\u00a0\u00a0 01111111\u00a0\u00a0\u00a0\u00a0\u00a0 DEL<\/p>\n

——————————————————————————-<\/p>\n

Say that you want to echo “Hi” with hex code, you do this:<\/p>\n

echo -e “\\x048\\x069”<\/p>\n

The \\x part is to let `echo -e` know that it’s hexa decimal code.
\nYou can even hide commands like that.<\/p>\n

Here is a script example of hiding the `top` command in hex and execute it:<\/p>\n

——————————————————————————-<\/p>\n

#!\/bin\/bash<\/p>\n

hexcode=’\\x074\\x06F\\x070’<\/p>\n

`echo -e $hexcode`<\/p>\n

——————————————————————————-<\/p>\n

This will execute what echo echos, due to the “`”‘s.
\nSo that script will actually start the `top` command.<\/p>\n

——————————————————————————-<\/p>\n

Another question I got a while back is how to make a DWORD (Double Word),
\nthat means how to rewrite an address or IP to hex\/oct\/dec.<\/p>\n

And it’s not that hard, all it takes is some mathematics.
\nIt works like this:<\/p>\n

There are several methods, but let’s start with the Decimal way
\nof making a DWORD.
\nSay you have IP: 127.0.0.1
\nthen you do:
\n127 * 16777216 = 2130706432
\n0 * 65536\u00a0\u00a0\u00a0\u00a0\u00a0 = 0
\n0 * 256\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = 0
\n1 * 1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = 1
\nSum:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2130706433<\/p>\n

Or if you have the IP: 123.123.123.123
\n123 * 16777216 = 2063597568
\n123 * 65536\u00a0\u00a0\u00a0 = 8060928
\n123 * 256\u00a0\u00a0\u00a0\u00a0\u00a0 = 31488
\n123 * 1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = 123
\nSum:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2071690107<\/p>\n

Note:
\n\u00a0\u00a0\u00a0\u00a0\u00a0 16777216 = 2^24
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 65536 = 2^16
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 256 = 2^8
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 = 2^0<\/p>\n

Next method is to convert it to HEX, OCT etc, to convert from dec to oct etc.
\nyou can either use the ascii table a few lines up, or you can download
\na program called ascii from www.freshmeat.net<\/a>.
\nLast time I saw it it was located at:
\nhttp:\/\/freshmeat.net\/projects\/ascii\/download\/ascii-3.0.tar.gz<\/a><\/p>\n

So assuming you have downloaded that and and wanna covert 127.0.0.1 and
\n123.123.123.123 to HEX DWORDs, do this:<\/p>\n

alien:~$ ascii 127 0 0 1
\nASCII 7\/15 is decimal 127, hex 7f, octal 177, bits 01111111: called ^?, DEL
\nOfficial name: Delete<\/p>\n

ASCII 5\/7 is decimal 087, hex 57, octal 127, bits 01010111: prints as `W’
\nOfficial name: Majuscule W
\nOther names: Capital W, Uppercase W<\/p>\n

ASCII 3\/0 is decimal 048, hex 30, octal 060, bits 00110000: prints as `0′
\nOfficial name: Digit Zero<\/p>\n

ASCII 3\/0 is decimal 048, hex 30, octal 060, bits 00110000: prints as `0′
\nOfficial name: Digit Zero<\/p>\n

ASCII 3\/1 is decimal 049, hex 31, octal 061, bits 00110001: prints as `1′
\nOfficial name: Digit One<\/p>\n

alien:~$<\/p>\n

Take the hex numbers after the decimal of 127, 0 and 1 and you’ll come
\nto the conclution that 127.0.0.1 in a hex DWORD is: 7F303031<\/p>\n

You can use OCT the same way .. with as many leading 0’s as you please<\/p>\n

0173.0173.0173.0173 or 000173.00000173.000173.000000000000000000000173,
\nit still means IP 123.123.123.123<\/p>\n

And ofcorse to add on the confusion you can mix the methods.
\n0173.0x7b.00173.123<\/p>\n

Now there is even more to this like that you can add any multiple of the
\nnumber 4294967296 (2^32) to the number without the IP changing ….
\nBut let’s not get into that ….<\/p>\n

So basically typing:
\nhttp:\/\/0173.0x7b.00173.123\/<\/a>
\nin your web browser will end you up at IP 123.123.123.132 (which doesnt excist)
\nbut the idea is the same for everything, so if you see some lame spammer
\nthinking that you wont know from what address he sent something …
\nThe just back count it and send abuse mail to his internet service provider.<\/p>\n

——————————————————————————-<\/p>\n

If someone has more questions mail, them to me at: alien@ktv.koping.se<\/a>
\nmaybe I’ll include them in the tutorial, but I’ll do my best to answer
\nthe questions anyway.<\/p>\n

===============================================================================
\n10 – Basics of the common UNIX and Linux text editors.
\n===============================================================================<\/p>\n

Here we go with the text editors vi, ed and emacs.
\ned is just explained for historical reasons.<\/p>\n

——————————————————————————-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Most commonly used VI commands
\n——————————————————————————-<\/p>\n

Here we go with the vi commands, these are unlogical but still good to know
\nbecause all computers doesn’t have emacs, joe, pico and so on.
\nSolaris \/ SunOS comes default with vi as only text editor.
\nVi has 2 basic modes, command mode and edit mode, you change between them
\nby pressing the Esc button, and to start to edit a file you must have a
\nfree line, which you get by pressing, Esc followed by `o`.
\nvi is bound to be the hardest and most confusing text editor to learn,
\nand it has LOTS of commands, I included just a few of the most used
\ncommands.<\/p>\n

So here we go with the vi commands:<\/p>\n

Inserting text<\/p>\n

esc + i\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 insert text informant of the cursor
\nesc + a\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 append text after the existing text
\nesc + O\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 opens new line above the current line
\nesc + o\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 opens new line under current line (insert mode)<\/p>\n

Deleting text<\/p>\n

esc + x\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes one character
\nesc + 5x\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes five charters
\nesc + dw\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes a word
\nesc + 5dw\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes five words
\nesc + dd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes the whole line
\nesc + D\u00a0\u00a0 deletes the line from cursor and forward
\nesc + d)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes the sentence from cursor and forward
\nesc + d(\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes the sentence from cursor and backwards
\nesc + u\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 undelete<\/p>\n

Note: esc + d) or d( removes the sentence from cursor and forward\/backwards
\nuntil it reaches a dot “.”<\/p>\n

Moving around in VI:<\/p>\n

Make sure you are in command mode and the following letters will do:<\/p>\n

j\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 moves you down
\nk\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 moves you up
\nh\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 moves you left
\nl\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 moves you right<\/p>\n

Finding Text<\/p>\n

Hit esc then type in a \/ you then go to the bottom of the screen
\nwhere you will see your \/ type in the text to look for.
\nie. \/Linux
\nthat will find the word `Linux` in the open file.<\/p>\n

Replacing Text<\/p>\n

Hit esc and do: :start,stop,s\/s_text\/r_text\/g<\/p>\n

:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 indicates that this is an ex command
\nstart\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is the starting line number
\nstop\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is the stopping point
\ns\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is the substitute command
\ns_text\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is the search string (the text you are looking for )
\nr_text\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is the text you are replacing with
\ng\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is global\u00a0<\/p>\n

Example:<\/p>\n

Esc + :5,8,s\/l\/ll\/g<\/p>\n

This would replace all “l”‘s with “ll” on lines 5 to 8.<\/p>\n

Note to Replacing Text:
\nLine numbers can also be:
\n.\u00a0 current line
\n$\u00a0 last line<\/p>\n

Basic save & quit commands<\/p>\n

Hit Esc and do a : where after you can type the commands.<\/p>\n

w\u00a0 write (save)
\nq\u00a0 quit
\n!\u00a0 force<\/p>\n

ie. :q!\u00a0 or\u00a0 :wq<\/p>\n

To create control characters do:<\/p>\n

Ctrl+V Ctrl+<the character><\/p>\n

Example:<\/p>\n

Ctrl+V Ctrl+A<\/p>\n

That will create a ^A character.<\/p>\n

(These last 3 commands are very alike ed commands)<\/p>\n

Another useful thing in VI is split-screen mode, so you can edit 2 files
\nat once, this is:<\/p>\n

:split<\/p>\n

Just press Esc and type “:split”.
\nYou can do this in most big editors ….. but ofcorse in another way, you’ll
\nsee when you’re reading the emacs section.<\/p>\n

——————————————————————————-
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Most commonly used ED commands
\n——————————————————————————-<\/p>\n

ed is a very very old line editor, and the grand father of most editors,
\nperhaps even the grandfather of all editors, it dates back to the time of
\nthe old CP\/M machines, and is the father of the old DOS edlin line editor.
\nSo out of historical perspective, it can be fun to know how to operate ed.<\/p>\n

Creating a file in ed:<\/p>\n

alien:~$ ed newfile
\nnewfile: No such file or directory<\/p>\n

Don’t worry, as soon as you save it it will create it.
\nED is pretty simple, here’s an example (the “(ed says)” and “(we type)” is
\njust there to make it easier to follow the editing in this tutorial and is
\nnot there in reality):<\/p>\n

alien:~$ echo “abcd” >> newfile; echo “efgh” >> newfile; echo “ijkl” >> newfile
\nalien:~$ ed newfile
\n15\u00a0 (ed says)
\n1,$ n\u00a0 (we type)
\n1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 abcd (ed says)
\n2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 efgh (ed says)
\n3\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ijkl (ed says)
\n1\u00a0 (we type)
\nabcd\u00a0 (ed says)
\ns\/ab\/ll\u00a0 (we type)
\nllcd\u00a0 (ed says)
\n$ n\u00a0 (we type)
\n3\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ijkl (ed says)
\na\u00a0 (we type)
\nhere we end (we type)
\n.\u00a0 (we type)
\nw\u00a0 (we type)
\n27\u00a0 (ed says)
\nq\u00a0 (we type)
\nalien:~$<\/p>\n

Not all that hard is it ?
\nHere’s a list of the most basic commands for ed:<\/p>\n

1,$ n\u00a0\u00a0\u00a0 displays all lines with numbers
\n$ n\u00a0 display last line, with number
\n2 n\u00a0\u00a0\u00a0\u00a0\u00a0 takes you to line 2
\ns\/new\/old\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 replaces old with new
\na\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 takes you to editor mode
\n.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 takes you to command mode
\nd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes line
\nw\u00a0 write file (save)
\nq\u00a0 quit<\/p>\n

——————————————————————————-<\/p>\n

The final thing in this tutorial is a really quick look at emacs commands:<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Most commonly used Emacs commands
\n——————————————————————————-<\/p>\n

^A Cursor to the beginning of line
\n^E Cursor to the end of line
\n^K Deletes rest of line forward
\n^D Deletes current character
\n^L Horizontally center the current line
\n^S Search for a word forward in the file
\n^R Search for a word backwards in file<\/p>\n

^Q Followed by Ctrl+<anything>, gives the real control character in a text file<\/p>\n

^X ^F Open file
\n^X ^- ^- Undo
\n^C+Shift+- Undo
\n^X ^C ! Quit without saving
\n^X 2 split screen (horizontaly)
\n^X 3 split screen (verticaly)
\n^X O move to other screen (if in splitscreen mode)
\n^X ^W Save As
\n^X ^S Save<\/p>\n

(^X 1 to get back a single window from splitscreen mode)<\/p>\n

Shift+Esc Shift+5: Replace query (press y to replace words)
\nMeta+backspace: Deletes rest of word backwards (note “Meta” == “Alt”)
\nHome: Takes cursor to the top of the file (Or equal to ^A)
\nEnd: Takes cursor to the end of the file (Or equal to ^E)
\nDelete: Deletes current character
\nPage Up \/ Page Down: Does what they say
\nMeta+X: Will load any emacs plugin, you may type any plugin name after pressing
\nthe Meta+X (Alt+X), if you press TAB here once you will get a list of the
\ncommands, if you type ‘a’ followed by a tab you will get all commands
\nstarting with a and so on …. try: Meta+X doctor to try the
\ninteractive eliza bot, or try telnet, ftp, webjump or shell.<\/p>\n

To reach the menus “Buffers Files …” etc. press F10
\nand if you wanna get out of the menus press ^G.<\/p>\n

You may think that all this is weird, but know that emacs use to work
\nas a VERY primitive window manager, before the times of X.<\/p>\n

Backspace and the arrow key’s works as normal.<\/p>\n

A tip is tp press: ^X then press 2 then press ^X and then O, now press
\nMeta+X and type ‘shell’, and you should have a split window, with a
\nshell in the lower one, so you can code or write in the upper one
\nat the same time as you have a shell in the lower one.
\nTo change between the windows simply press: Ctrl+X and then press: o
\nA note is that if you want to run BitchX in the shell part you need
\nto start it with: BitchX -d, to get it in dumb terminal mode.<\/p>\n

Usless or obsolete commands:<\/p>\n

^I TAB
\n^O Move text forward
\n^P same as UpArrow
\n^F same as RightArrow
\n^J Enter\/Return
\n^B same as LeftArrow
\n^N same as DownArrow
\n^M Enter\/Return<\/p>\n

^U Del\u00a0 deletes 4 characterss backwards
\n^U ^U Del\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 deletes 16 characterss backwards
\n^U ^U ^U Del\u00a0\u00a0\u00a0 deletes 64 characterss backwards<\/p>\n

All you really need to know to start using emacs is how to save and quit.<\/p>\n

( ^X ^S ^X ^C will save and quit, a tip is: hold down ^ (Ctrl) and
\npress X S X C )<\/p>\n

===============================================================================
\n——————————————————————————-
\n===============================================================================<\/p>\n

This should be enough for you to start to script in bash, and make useful
\nscripts.
\nThe only thing that limits what you can do is your imagination (well almost).<\/p>\n

Go over this tutorial several times so you really understand everything.
\nIf you accomplish that, you have a really good chance of learning UNIX well.<\/p>\n

And that’s what it’s all about, to learn new things and explore new ways.
\nAs long as you learn you live, not the contrary.<\/p>\n

This tutorial turned out rather large, but I hope that those of you out there
\nthat have the determination to learn shell scripting, also have the patinace
\nto read it all, and if not, you can always use it as a small dictionary.<\/p>\n

I’ve got the question many times, which Linux distribution is the best ….
\nThe question in it self is pointless and as ilitterat as asking
\nwhat version linux is up to….
\nThe later question can only be answerd with a kernel version number,
\nand that is what Linux is, Linux is the kenrel and all distributions
\nuse the same kernel, everything else in the system is just “stuff around
\nthe kernel”, to this point I’ve found that Mandrake is the distibution
\nthat is most compleat for my needs, and it’s suitable for beginners
\naswell as for proffessionals, and it has nice configuration tools
\nthat have been written especially for Mandrake.
\nBut as I said, a Linux is a Linux, and the main difference between different
\ndistributions is the package manager, where of rpm is the most stanard
\nand accepted, though I find Debians dpkg good aswell.
\nThis is to the difference of distributions that have no indiginous package
\nmanager like Slackware, that emulates a package manager with it’s .tgz
\npackage format (note that .tar.gz is not .tgz since .tgz should have it’s
\npackages compressed with there path beginning from \/ )
\nNow there is nothing wrong with that if you like to compile most stuff on the
\nsystem your self, and many people preffer to do that.<\/p>\n

My conclution is that the best distrinution is the one you personally
\nlike the best, the one that fits _your_ needs.<\/p>\n

So anyway, when you know bash scripting well enough, my suggestion is to
\nlearn C programming, which, if you look at it with bash behind you,
\nisn’t that hard.<\/p>\n

So, I better go to bed and stop this nonses now.<\/p>\n

Happy scripting all of you out there.<\/p>\n

===============================================================================
\n————— Written by Billy Wideling <-> alien@koping.net<\/a> —————-
\n===============================================================================<\/p>\n","protected":false},"excerpt":{"rendered":"

original link: http:\/\/subsignal.org\/doc\/AliensBashTutorial.html =========================== Aliens Bash Tutorial ============================== ————— Written by Billy Wideling <-> alien@koping.net —————- =============================================================================== First you probably need to read a UNIX command bible to really understand this tutorial, but I will try to make it as clear as possible, there is about 100-150 UNIX commands explained later in this tutorial. You […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-9","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/wp.oktay.com\/index.php?rest_route=\/wp\/v2\/pages\/9","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.oktay.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/wp.oktay.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/wp.oktay.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.oktay.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9"}],"version-history":[{"count":0,"href":"https:\/\/wp.oktay.com\/index.php?rest_route=\/wp\/v2\/pages\/9\/revisions"}],"wp:attachment":[{"href":"https:\/\/wp.oktay.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}