title: Controlling processes from Python
body: <p>I want to control several subprocesses of the same type from python (I am under linux).
  I want to:</p>
  
  <ul>
  <li>Start them.</li>
  <li>Stop them.</li>
  <li>Ask if they are still running.</li>
  </ul>
  
  <p>I can start a processes with with spawnl, and get the pid. Using this pid I can stop it with kill. And I am sure there is also a way to ask if it is running with the pid.</p>
  
  <p>The problem is, what if the following happens:
  I start a process, remember the pid. The process ends without me noticing and another completely different process starts getting assigned the same pid. I attempt to kill my process, I kill a completely different one.</p>
  
  <p>What is the better way to start and control processes in python?
  Thanks! </p>