Question

I looked at this page and can’t understand how this works.

This command ‘exponentially spawns subprocesses until your box locks up’.

But why? What I understand less are the colons.

user@host$ :(){ :|:& };:

Answer 1

That defines a function called : which calls itself twice (Code: : | :). It does that in the background (&). After the ; the function definition is done and the function : gets started.

So every instance of : starts two new : and so on… Like a binary tree of processes…

Written in plain C that is:

fork(); fork();