Disable console output from subprocess.Popen in Python

Question

I run Python 2.5 on Windows, and somewhere in the code I have

subprocess.Popen("taskkill /PID " + str(p.pid))

to kill IE window by pid. The problem is that without setting up piping in Popen I still get output to console – SUCCESS: The process with PID 2068 has been terminated. I debugged it to CreateProcess in subprocess.py, but can’t go from there.

Anyone knows how to disable this?

Asked By: Denis Masyukov

||

Source

Answer 1

fh = open("NUL","w")
subprocess.Popen("taskkill /PID " + str(p.pid), stdout = fh, stderr = fh)
fh.close()

Answered By: Mark

Answer 2

from subprocess import check_call, DEVNULL, STDOUT

check_call(
    ("taskkill", "/PID", str(p.pid)),
    stdout=DEVNULL,
    stderr=STDOUT,
)

I always pass in tuples (or lists) to subprocess as it saves me worrying about escaping. check_call ensures (a) the subprocess has finished before the pipe closes, and (b) a failure in the called process is not ignored.

If you’re stuck in python 2, subprocess doesn’t provide DEVNULL. However, you can replicate it by opening os.devnull (the standard, cross-platform way of saying NUL in Python 2.4+):

import os
from subprocess import check_call, STDOUT

DEVNULL = open(os.devnull, 'wb')
try:
    check_call(
        ("taskkill", "/PID", str(p.pid)),
        stdout=DEVNULL,
        stderr=STDOUT,
    )
finally:
    DEVNULL.close()

Answered By: Alice Purcell

Disable console output from subprocess.Popen in Python

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