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WarrenFaith
Asked: 2011-06-09 09:43:47 +0800 CST

Understanding this shell statement

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I admit it is a homework but I am lost in explaining the following command line:

WARNING: This is a so called FORK BOMB! This command line can and will crash your pc by consuming all RAM and CPU (trust me, I tried it...)

:(){ :|:& };:

As I know that I should do it alone here is what I have so far (searching for these chars is very discouraging).

  1. The pipe enables to concatenate some commands together so that the first output is used by the second as input.
  2. The & is to run a command in the background (basically used to start something from a shell which shouldn't be blocked by the command)

I guess that : is to fork? But here I am totally lost! I am willing to learn, so maybe someone have a good resource where I can read about that?

command-line

1 Answers

  1. Best Answer
    :()      # define ':' -- whenever we say ':', do this:
{        # beginning of what to do when we say ':'
    :    # load another copy of the ':' function into memory...
    |    # ...and pipe its output to...
    :    # ...another copy of ':' function, which has to be loaded into memory
         # (therefore, ':|:' simply gets two copies of ':' loaded whenever ':' is called)
    &    # disown the functions -- if the first ':' is killed,
         #     all of the functions that it has started should NOT be auto-killed
}        # end of what to do when we say ':'
;        # Having defined ':', we should now...
:        # ...call ':', initiating a chain-reaction: each ':' will start two more.

    Source: Forkbombs on Wikipedia

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