An introduction to services, runlevels, and rc.d scripts

A coOl link explaining about Linux's /etc/rc* and /etc/inittab subsystem architecture.

http://www.linux.com/news/enterprise/systems-management/8116-an-introduction-to-services-runlevels-and-rcd-scripts

fork() bomb

Coding can never become more interesting than this !!!
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Understanding :(){ :|:& };: fork() bomb code

 :() - It is a function name. It accepts no arguments at all.

Generally, bash function is defined as follows:

foo(){
 arg1=$1
 echo ''
 #do_something on $arg argument
}

fork() bomb is defined as follows:

:(){
   :|:&
};:

:|: - Next it call itself using programming technique called recursion and pipes the output to another call of the function ':'. The worst part is function get called two times to bomb your system.

& - Puts the function call in the background so child cannot die at all and start eating system resources.

; - Terminate the function definition

: - Call (run) the function aka set the fork() bomb.

Here is more human readable code:

bomb() {
bomb | bomb &
}; bomb

Properly configured Linux / UNIX box should not go down when fork() bomb sets off.

REFERENCE : http://www.cyberciti.biz/faq/understanding-bash-fork-bomb/
WIKI : http://en.wikipedia.org/wiki/Fork_bomb

OProfile manual

1. OProfile Manual by John Levon
http://oprofile.sourceforge.net/doc/index.html

 2. OProfile Tutorial
http://linuxtips.pbworks.com/Oprofile-Tutorial

Insight into GNU/Linux boot process

A very detailed description of what happens during Linux boot process

http://unixbhaskar.blogspot.com/2010/03/insight-into-gnulinux-boot-process.html
Author : Bhaskar Chowdhury