When cancelling a Python script do something

Question

When i press CTRL+C to cancel a running python script, is there a way to run a certain python code before the script terminates?

You can catch the `KeyboardInterrupt` error; or you can set up [a signal handler](http://stackoverflow.com/a/1112350/344643); or you can do something at exit time [using the atexit module](http://docs.python.org/2/library/atexit.html#atexit-example). — Waleed Khan, Dec 08 '13 at 21:54

score 6 · Answer 1 · 2013-12-08T22:18:12.470

6

Use try/except to capture for KeyboardInterrupt, which is raised when you press CTRL+C.

Here is a basic script to demonstrate:

try:
    # Main code
    while True:
        print 'hi!'
except KeyboardInterrupt:
    # Cleanup/exiting code
    print 'done!'

This will continually print 'hi!' until you press CTRL+C. Then, it prints 'done!' and exits.

edited Dec 08 '13 at 22:18

answered Dec 08 '13 at 21:54

score 1 · Answer 2 · answered Dec 08 '13 at 21:55

1

CTRL+C raises KeyboardInterrupt. You can catch it just like any other exception:

try:
    main()
except KeyboardInterrupt:
    cleanup()

If you really don't like that, you can also use atexit.register to register cleanup actions to run (provided that you don't do something really nasty and cause the interpreter to exit in a funky way)

answered Dec 08 '13 at 21:55

mgilson

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`atexit.register` is an excellent alternative. – SethMMorton Dec 08 '13 at 22:00

score 0 · Answer 3 · answered Dec 08 '13 at 21:55

0

try:
    # something
except KeyboardInterrupt:
    # your code after ctrl+c

answered Dec 08 '13 at 21:55

mchfrnc

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Deck · Answer 4 · 2013-12-08T22:02:00.483

0

This code

import time 

try:
    while True:
        time.sleep(2)
except KeyboardInterrupt:
    print "Any clean"

gives

deck@crunch ~/tmp $ python test.py 
^CAny clean

when I press Ctrl+C when executing.
You just have to handle KeyboardInterrupt exception.

Also you can deal with signals to set handlers.

edited Dec 08 '13 at 22:02

answered Dec 08 '13 at 21:56

Deck

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score 0 · Answer 5 · answered Dec 08 '13 at 21:57

I'm pretty sure you just need a try/finally block.

Try out this script:

import time

def main():
    try:
        while True:
            print("blah blah")
            time.sleep(5)
    except KeyboardInterrupt:
        print("caught CTRL-C")
    finally:
        print("do cleanup")

if __name__ == '__main__':
    main()

Output should be something like:

blah blah
caught CTRL-C
do cleanup

When cancelling a Python script do something

5 Answers5