nonblocking-subprocess.py

import subprocess
import select
import os
import sys
import fcntl

p1 = subprocess.Popen("sleep 2 && echo done1 && sleep 5 && echo done2",
                      shell=True, stdout=subprocess.PIPE)
p2 = subprocess.Popen("sleep 3 && echo done3 && sleep 5 && echo done4",
                      shell=True, stdout=subprocess.PIPE)

pout = [p1.stdout.fileno(), p2.stdout.fileno()]
for fd in pout:
    fl = fcntl.fcntl(fd, fcntl.F_GETFL)
    fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)

fd1_closed, fd2_closed = 0, 0
while not (fd1_closed and fd2_closed):
    inputready, outputready, exceptready = select.select(pout, [], [])
    for s in inputready:
        got = os.read(s, 1)
        if got:
            print "got output %s from fd %d" % (got, s)
        else:
            if s == pout[0]:
                fd1_closed = 1
            elif s == pout[1]:
                fd2_closed = 1
            else:
                pass