how to trap suspend signal

[Mauro Gatti]

Hi all,
I'd like to trap ctrl+z (suspend ?) signal.

I think to do something like this :

trap s

s () {
....

}

It is correct?
is 24?

Thank You

[Shannon Petry]

Looks correct. If you look a bit into the trap, you can also trap multiple system calls.
I.E.

trap 'exit_fc' 1 2 3 4 5 6 7

exit_fc() {
# do stuff here...
}

Regards,
Shannon

[Rick Tuck · Accepted solution]

I don't think you can trap a signal 24, but in my testing I trapped a signal 25 just fine which prevented the users from using ctrl-z.

[Olivier ROBERT]

Hi,

Signal 24 is SIGSTOP, which cannot be caught or ignored, hence not trap'ed. But eventually, SIGTSTP (number 25) is sent when you press CTRL+Z. The default behaviour of SIGTSTP is to trigger a SIGSTOP, but this one can be caught or ignored, hence trap'ed. So you have to use signal 25 instead of signal 24.
Regards,

Olivier