Question

Currently I am using the python os.system(cmd) to do some daily works.

Here is one situation, the cmd will take 5-6 minutes to finish, and I run this cmd maually, it works, but when I put it into os.system(cmd), os.system(cmd) will automatically exit when the cmd is not finished yet.

So my question is: how to handle this issue, set timeout value or there is any better way to finish this job ?

Thanks in advance!

Answer 1

Have you tried the subprocess module? It was added to replace os.system among other older os methods. The following is pretty much straight from the docs:

import os
import subprocess

proc = subprocess.Popen(cmd, shell=True)
pid, sts = os.waitpid(proc.pid, 0)

# you may check on this process later and kill it if it's taking too long
if proc.poll() in [whatever, ...]:
    os.kill(proc.pid)

or if you’re trying to debug why the process is exiting:

import subprocess
import sys

try:
    retcode = subprocess.call(cmd, shell=True)
    if retcode < 0:
        print >>sys.stderr, "Child was terminated by signal", -retcode
    else:
        print >>sys.stderr, "Child returned", retcode
except OSError, e:
    print >>sys.stderr, "Execution failed:", e