title: Launch linux command via python subprocess doesn't work as expected
body: <p>I'm trying to kill a specific python process launched earlier, lets call it <code>test.py</code>.<br>
  The command in linux which terminates it is : <code>sudo pkill -f test.py</code>->  works like a charm.   </p>
  
  <p>However when trying to launch via python code:<br>
  <code>subprocess.Popen('sudo pkill -f test.py', stdout=subprocess.PIPE)</code><br>
  I get a stacktrace with <code>OSError: [Errno 2] No such file or directory</code>  </p>
  
  <p>Any idea what am I doing wrong?</p>