Is it possible to enforce a certain exit code when using “kill” to stop a process?

Question

Is it possible to enforce a certain exit code when using "kill" to stop a process?

do you mean that you want the program to be killed returning a certain code? or you want to send a certain type of signal by using kill? or that in your custom application, when a user sends a kill signal, you perform some action?
i mean the first option you mention, i.e. force the program to be killed return a certain code. sorry for not being clear enough

Dennis Williamson · Answer 1 · 2011-02-09 15:58:03Z

up vote 1 down vote accepted

This will exit with a 42 if any of the listed signals are received. You could perform other actions including calling a function, etc.

#!/bin/bash
trap 'exit 42' SIGINT SIGQUIT SIGTERM

answered Feb 9 '11 at 15:58

	this does not quite solve my problem. probabely it makes sense to step out a bit and explain what i am trying to do: i have a shell script that starts a process, and in case the process exits with code 0, restarts it. now in some cases i want to restart the process manually i which case it would be nice to just call 'kill PID'. however, kill does not necessarily return with code 0. it would be nice to enforce this. does this make sense to you? – ralf Feb 9 '11 at 17:03
	@ralf: Would `(kill PID; exit 0)` (doing the kill in a subshell with an unconditional `exit 0`) work for you? The only time `kill` should return non-zero is if there's an error (e.g. no such process or invalid option). You should also take a look at Process Management. – Dennis Williamson Feb 9 '11 at 17:10
	will try this out. thanks too for the provided link – ralf Feb 11 '11 at 16:04

feedback

rems · Answer 2 · 2011-02-09 12:17:12Z

Yes, you have the trap the kill signals you send to your script using the trap command, see man bash and look for the trap command.

After "trapping" the signal sent to the script, you could exit with any value you want to.

2 Answers