#!/usr/bin/env python

import subprocess

# use sequence of arguments
ret = subprocess.call(['echo', 'Hello world!'])
# shell=True allows to use simple string for the command
ret = subprocess.call('echo Hello world!', shell=True)
print()

command = 'date'
print(command)
# checks output, raises error if nonzero return code
output = subprocess.check_output(command, shell=True) 

p = subprocess.Popen('date', stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True) 
out, err = p.communicate() 
returncode = p.returncode

#return_code = p.wait() 

print(output.decode('utf-8')) 
print('out:', output.decode('utf-8')) 
print('err:', err.decode('utf-8')) 
print('status:', returncode) 


# write to stdout and logfile

logfile = open('logfile', 'w')
proc=subprocess.Popen(['cat', 'file'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
for line in proc.stdout:
    sys.stdout.write(line)
    logfile.write(line)
proc.wait()