proc.py

import subprocess
import atexit

proc = subprocess.Popen("ping google.com", shell = True, stdout = subprocess.PIPE, stderr = subprocess.STDOUT)

# register terminate function if python script is killed
atexit.register(proc.terminate)

for line in iter(proc.stdout.readline, ""):
    print "got line: '%s'" % line

# setup the proc return code
proc.poll()

#while proc.poll() is None:
#    print "waiting"
#    nextline = proc.stdout.readline()
#    if nextline != "":
#        print nextline

print "process with pid %s is finished with return code %s" % (proc.pid, proc.returncode)