BASH - What does _(){ _|_&}; _ do? [duplicate]

Question

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The Bash command :(){ :|:& };: will spawn processes to kernel death. Can you explain the syntax? (4 answers)

Closed 8 years ago.

I'm guessing the {} expansion results in something like

_() _  _()_&; _

but I would appreciate if a BASH guru chimed in and explained those characters chaining actions.

Answer 1

It's the classic fork bomb: it defines a function named _ that calls itself twice (once in the foreground and once in the background) and calls it:

bomb(){ bomb | bomb &}; bomb

---

bomb() {
    bomb | bomb&
};

bomb

http://en.wikipedia.org/wiki/Fork_bomb