Python : Use Popen and Communicate and get the stdout in a loop - python-2.7

Question

I want to execute bash command and get the output and I decided to use Popen and Communicate to do this. this job has to be done in a loop. The problem is that in the first round of loop every thing is OK but in the next loops I get Error when using communicate function. I know that communicate function can only be used once but I create a new subprocess each loop and therefore running communicate should be possible .
Here's the Code:
with open('ComSites2.txt') as file:
for site in file:
sf = site.split()
temp = "http://wwww." + sf[0]
command = "wget --spider -S '%s' 2>&1 | grep 'HTTP/' | awk '{print $2}'" %temp
print command
output = subprocess.Popen(command,stdout=subprocess.PIPE, shell=True)
StatusCode = int(output.communicate()[0])
if StatusCode == 200:
print "page found successfully"
elif StatusCode == 404:
print "Page not found!!"
else:
print "no result got!!"
when I run this I get this output :
wget --spider -S 'http://wwww.ACAServices.com' 2>&1 | grep 'HTTP/' | awk '{print $2}'
page found successfully
wget --spider -S 'http://wwww.ACI.com' 2>&1 | grep 'HTTP/' | awk '{print $2}'
Traceback (most recent call last):
File "/root/AghasiTestCases/URLConnector.py", line 17, in <module>
StatusCode = int(output.communicate()[0])
ValueError: invalid literal for int() with base 10: ''