I think by "out of the picture" PP meant that the shell is not processing the input, not that it has exited. C-z is not processed by the shell but by the termi

I think by "out of the picture" PP meant that the shell is not processing the input, not that it has exited. C-z is not processed by the shell but by the terminal "infrastructure". You can disable it, or change the key binding, and a lot more, with stty(1).