[ILUG] Terminate process after a set time limit

[Kieran Tully]

On 11/3/06, Pádraig Brady <P at draigbrady.com> wrote:
> > Kieran Tully wrote:
> >
> >>Is there a standard way to impose a time limit on a child process, and
> >
> > I guess you could do it with trap?
> >
> > #!/bin/sh
> > trap exit 17
> > sleep 900&
> > potentially_long_command

I tried this yesterday, but couldn't get SIGCHLD to trigger.
I knocked up a script using kill -ALRM $$ instead.
It worked, but there were some cleanup subtleties I had yet to iron
out, at which point I was going to post the script, but you beat me to
it!

> Did this on the train this morning:
> http://www.pixelbeat.org/scripts/timeout

Thanks for that. From what I can see, the set -m in your script is
necessary for the SIGCHLD approach to work in non-interactive shells.

As your comments point out, a script with a similar purpose lives at
/usr/share/doc/bash*/scripts/timeout

But it busy-waits, and there is a race condition, as the PIDs to kill
could be reallocated between busy-wait intervals (may explain why it's
not executable by default on the systems I checked!).

So I may well go with your script. Thanks again,
-- 
Kieran Tully, Software Developer and Tenor, http://kieran.tul.ly