Signals with trap


I am preparing a small class for students on signals with trap. I understood the use of this principle with the example on signal 2 SIGINT:

trap “echo hello” 2: which displays “hello” each time you press the shortcut ctrl + c.

On the other hand, I have difficulty assimilating the use of the following cases:

  1. The effect of signal 3 SIGQUIT.

  2. The effect of siganl 9 SIGKILL.

  3. The effect of the signal 19 SIGSTOP.

Can you guide me with simple examples please?

Best regard

I’m pretty sure SIGKILL and SIGSTOP cannot be trapped (or handled at all).


[b]Ctrl+[/b] will send a SIGQUIT signal to the terminal, so maybe

trap "bash -c /usr/bin/gedit" 3

then [b]Ctrl+[/b] should fire up /usr/bin/gedit