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:
The effect of signal 3 SIGQUIT.
The effect of siganl 9 SIGKILL.
The effect of the signal 19 SIGSTOP.
Can you guide me with simple examples please?