How can I run an external command asynchronously f

Question

I need to run a shell command asynchronously from a Python script. By this I mean that I want my Python script to continue running while the external command goes off and does whatever it needs to do.

I read this post:

Calling an external command in Python

I then went off and did some testing, and it looks like os.system() will do the job provided that I use & at the end of the command so that I don't have to wait for it to return. What I am wondering is if this is the proper way to accomplish such a thing? I tried commands.call() but it will not work for me because it blocks on the external command.

Please let me know if using os.system() for this is advisable or if I should try some other route.

Answer 1

I've had good success with the asyncproc module, which deals nicely with the output from the processes. For example:

import os
from asynproc import Process
myProc = Process("myprogram.app")

while True:
    # check to see if process has ended
    poll = myProc.wait(os.WNOHANG)
    if poll is not None:
        break
    # print any new output
    out = myProc.read()
    if out != "":
        print out