topic Re: How to stop an endless loop with trap? in Operating System - HP-UX

How to stop an endless loop with trap?

cybermilky — Sat, 19 Oct 2002 01:07:02 GMT

How do I stop my while loop by using 'trap'? I don't want my shell script to use ctrl-c.
-------------
#!/bin/sh
trap '???' ? #Problem: How to trap?
while:
do
echo Program is looping
done
-------------
How can I kill it while I'm having an endless loop?

Re: How to stop an endless loop with trap?

harry d brown jr — Sat, 19 Oct 2002 01:37:41 GMT

Write better scripts, by not having infinite loops! That's the first rule of programming.

live free or die
harry

Re: How to stop an endless loop with trap?

harry d brown jr — Sat, 19 Oct 2002 10:16:59 GMT

give this link a once over:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x022718276953d61190040090279cd0f9,00.html

live free or die
harry

Re: How to stop an endless loop with trap?

Wodisch_1 — Sat, 19 Oct 2002 11:54:42 GMT

Hi,

well, why not use signal #1 (SIGHUP) and send that signal from another shell-session to that running script?

trap "echo trapped" 1 # set trap
#your loop here
trap "" 1 # release trap

Now you start it, say into the background:

./your-script & # now $! is the PID of this process
pid=$!

And finally, as soon as you decide to stop it:

kill -1 $pid

HTH,
Wodisch