title: Running a command only once from a script, even script is executed multiple times
body: <p>I need some help. I'm having a script 'Script 1', which will call 'Script 2' to run in background which checks something periodically. But I want the Script 2 to get started only once, even Script 1 is called multiple times. Is there a way to do it?</p>
  
  <p>It would be even more helpful, if someone suggests some commands to achieve this.</p>
  
  <p>Thanks in advance</p>