And on a modern Linux system, there’s a limit to how many can run simultaneously, so while it will bog down your system, it won’t crash it. (I’m running it right now)
That would only add one extra process instance with each call. The pipe makes it add 2 extra processes with each call, making the number of processes grow exponentially instead of only linearly.
Edit: Also, Im not at a computer to test this, but since the child is forked in the background (due to &), the parent is free to exit at that point, so your version would probably just effectively have 1-2 processes at a time, although the last one would have a new pid each time, so it would be impossible to get the pid and then kill it before it has already replaced itself. The original has the same “feature”, but with exponentially more to catch on each recursion. Each child would be reparented by pid 1, so you could kill them by killing pid 1 i guess (although you dont want to do that… and there would be a few you wouldn’t catch because they weren’t reparented yet)
How did this one work again? It was something with piping in a backgrounded subshell, right?
It creates a new process that spins up 2 new instances of itself recursively.
https://itsfoss.com/fork-bomb/
And on a modern Linux system, there’s a limit to how many can run simultaneously, so while it will bog down your system, it won’t crash it. (I’m running it right now)
man ulimit
I just did this in zsh and had to power off my machine. :(
Thanks, nice Infographic!
Not mine, grabbed it from the link, but it’s a great explanation!
does this constitute a quine? I wrote a couple quines using bash but nothing as elegant as this
Maybe I’m missing something, but I think this doesn’t print or otherwise reproduce its own source code, so it’s not a quine afaict.
Correct. A quine is a program that prints its own source code. This one doesn’t print anything.
thank you,
tom jones lesser known single
Goodness, gracious, fork bomb in bash
Thanks friend. One question, is it necessary to pipe to itself? Wouldnt : & in the function body work with the same results?
That would only add one extra process instance with each call. The pipe makes it add 2 extra processes with each call, making the number of processes grow exponentially instead of only linearly.
Edit: Also, Im not at a computer to test this, but since the child is forked in the background (due to &), the parent is free to exit at that point, so your version would probably just effectively have 1-2 processes at a time, although the last one would have a new pid each time, so it would be impossible to get the pid and then kill it before it has already replaced itself. The original has the same “feature”, but with exponentially more to catch on each recursion. Each child would be reparented by pid 1, so you could kill them by killing pid 1 i guess (although you dont want to do that… and there would be a few you wouldn’t catch because they weren’t reparented yet)
I may be wrong, but you could use : &;: & as well, but using the pipe reduces the amount of characters by two (or three, counting whitespace)