Why does pressing Ctrl-backslash result in core dump?

Question

When I'm in a python application (the python shell, for instance), pressing ctrl + \ results in

>>> Quit (core dumped)

Why is this, and how can I avoid this? It is very inconvenient if application bails out whenever I press ctrl + \ by accident.

Depilatory

For me it only quits, but does not dump. I don't know why it quits in the first place, but that it dumps core might indicate a problem with your python installation. – Fulllength

CTRL + \ is a default shortcut for sending SIGQUIT to foreground process. By default, SIGQUIT causes a core dump. More in man kill. If you wish, you can remove the shortcut from your terminal perferences. – Hexastich

That's weird, because it doesn't happen when I'm in nano or vim for instance. – Depilatory

Nano and Vim take special care to intercept ^C, ^Z and ^\. Most programs accept the default behavior, as Python does. – Kirksey

It breaks sudo on my machine because quitting ipython this way changes the output of stty – Bigmouth

Answer 1

The python module signal is convenient to deal with this.

import signal

# Intercept ctrl-c, ctrl-\ and ctrl-z
def signal_handler(signal, frame):
    pass
signal.signal(signal.SIGINT, signal_handler)
signal.signal(signal.SIGQUIT, signal_handler)
signal.signal(signal.SIGTSTP, signal_handler)

Just add handlers to the signal that (in this case) do nothing.

Depilatory

Answer 2

CTRL-\ is the Linux key that generates the QUIT signal. Generally, that signal causes a program to terminate and dump core. This is a feature of UNIX and Linux, wholly unrelated to Python. (For example, try sleep 30 followed by CTRL-\.)

If you want to disable that feature, use the stty command.

From the Linux command line, before Python starts:

stty quit undef

Maidinwaiting

while this works for the python shell, ipython still quits even though quit has been undefed – Rh