#!/usr/bin/python2.4
import subprocess

a = subprocess.Popen(('dd','if=/dev/zero','bs=1M','count=1k'), stdout=subprocess.PIPE)
b = subprocess.Popen(('dd','of=/dev/null'), stdin=a.stdout)

r = a.communicate()
if r == None:
	print "a: None"
else:
	for s in r:
		print "a: %s" % (s != None)
print a.returncode

r = b.communicate()
if r == None:
	print "b: None"
else:
	for s in r:
		print "b: %s" % (s != None)
print b.returncode