title: Validate input from bash
body: <p>I need to make a bash script that takes user input and does some validation.  </p>
  
  <p>The input is small. I just need to get a user choice "yes" or "no" and a file path and make sure the input is indeed a filepath and that he entered yes or no. </p>
  
  <p>How can I validate the user input? </p>