title: How to get PID of the subprocess with subprocess check_output
body: <p>In my python script I'm trying to run some long lasting download process, like in the example below, and need to find a PID of the process started by check_output: </p>
  
  <pre><code>out = subprocess.check_output(["rsync","-azh","file.log",...])
  </code></pre>
  
  <p>Is it possible to do? </p>