python captures the output instance of the shell and bash script

#!/usr/bin/python
## get subprocess module
import subprocess

## call date command ##
p = subprocess.Popen("date", stdout=subprocess.PIPE, shell=True)

## Talk with date command i.e. read data from stdout and stderr. Store this info in tuple
## Interact with process: Send data to stdin. Read data from stdout and stderr,
## until end-of-file is reached.Wait for process to terminate. The optional input
## argument should be a string to be sent to the child process, or None,
## if no data should be sent to the child. ##
(output, err) = p.communicate()

## Wait for date to terminate. Get return returncode ##
p_status = p.wait()
print "Command output : ", output
print "Command exit status/return code : ", p_status

## from: http://www.cyberciti.biz/faq/python-run-external-command-and-get-output/