start python script as background process from within a python script

Question

My python script needs to start a background process and then continue processing to completion without waiting for a return.

The background script will process for some time and will not generate any screen output.

There is no inter-process data required.

I have tried using various methods subprocess, multiprocessing but am clearly missing something.

Does anyone have a simple example?

TIA

score 3 · Accepted Answer · answered Aug 29 '10 at 17:46

3

how about this:

import subprocess
from multiprocessing import Process

Process(target=subprocess.call, args=(('ls', '-l', ), )).start()

It's not all that elegant, but it fulfils all your requirements.

answered Aug 29 '10 at 17:46

Stefano Palazzo

score 2 · Answer 2 · answered Aug 29 '10 at 17:42

2

Simple:

subprocess.Popen(["background-process", "arguments"])

If you want to check later whether the background process completed its job, retain a reference to the Popen object and use it's poll() method.

answered Aug 29 '10 at 17:42

Marius Gedminas

score 1 · Answer 3 · edited May 23 '17 at 12:07

1

There is a nice writeup of the various pieces/parts on how to do it at Calling an external command in Python (per @lecodesportif).

The gist of a quick answer is:

retcode = subprocess.call(["ls", "-l"])

edited May 23 '17 at 12:07

Community

answered Aug 29 '10 at 17:19

heckj

It fails the "without waiting" requirement. – Marius Gedminas Aug 29 '10 at 17:39
1

Ah - my bad, I missed that in the reading. You're quite correct. Stefano's answer should do what you want then. – heckj Aug 29 '10 at 18:07
What about something like: `retcode = subprocess.call(["ls -l &"], shell=True)`. That works for me. – SunSparc May 21 '13 at 21:33

3 Answers3