Stopping a Process in Python

python python-2.7 subprocess popen os.system
CodyJHeiser picture CodyJHeiser · Jun 21, 2014 · Viewed 12.4k times · Source

I am running a program that I would like to have stopped when a certain button is pushed.

I was thinking of running the process in the background so that the button can be pressed any time during the process and it would stop it.

I read stuff on subprocess from the documentation, but me being a beginner I have no idea how to use it, any help is appreciated.

def put(command):
        os.system(command)

        if direct == "":
            time.sleep(.5)
            arg1 = put("sudo ffmpeg -i \"" + q3 + "\" -f s16le -ar 22.05k -ac 1 - | sudo ./pifm - " + str(freq)) 
            subprocess.Popen(arg1)
            while True:
                if RPIO.input(25) == GPIO.LOW: #if button is pushed, kill process (arg1)
                    Popen.terminate()

Answer

Serge Ballesta picture Serge Ballesta · Jun 21, 2014

If you want to keep control on your subprocess, you'd better use the subprocess module. If you create it via Popen, you will be able to stop it via the kill() or terminate() methods.

Example

import subprocess
# ...
sub = subprocess.Popen(command)
# ...
sub.kill()

And you are sure you are killing your own child, even if there are numerous command running simutaneously

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