Signals with trap

baouche

Hello,

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 regards.