gist copied from http://stackoverflow.com/questions/1996518/retrieving-the-output-of-subprocess-call

run_shell.py

import shlex
from subprocess import Popen, PIPE

def run_shell(cmd):
    """
    Execute the external command and get its exitcode, stdout and stderr.
    """
    args = shlex.split(cmd)

    proc = Popen(args, stdout=PIPE, stderr=PIPE)
    out, err = proc.communicate()
    rc = proc.returncode
    #
    return rc, out, err

cmd = "..."  # arbitrary external command, e.g. "python mytest.py"
rc, out, err = run_shell(cmd)