title: "label" for process to be able to kill it by "label"
body: <p>I need to run more player programs at once (in linux), but I want to kill it by subprocess separately. So I am thinking about something like adding "label" for each player process when I start it, e.g. player "1", player "2", player "3", player "3", player "3" and then I would like to call subprocess to kill all instances of player "3".</p>
  
  <p>How to do this?</p>