title: Duplicate instances of same linux process
body: <p>I have a script which does the following w.r.t a linux process-</p>
  
  <ul>
  <li><p>To start a process, check if the process is already running. If it is running, then display suitable message and exit. If the process is not running, then start it.</p></li>
  <li><p>To stop a process, check if the process is not running. If it is not running, then display suitable message and exit. If the process is running, then stop it.</p></li>
  </ul>
  
  <p>To summarize, I want to instantiate a process only once. But the issue is when I attempt to instantiate again, it is creating another instance. And the PPID of both instances is 1. Need an expert opinion on this.</p>