title: How to check that a parameter was supplied to a bash script
body: <p>I just want to check if one parameter was supplied in my bash script or not. </p>
  
  <p>I found <a href="https://stackoverflow.com/questions/699576/validating-parameters-to-a-bash-script">this</a>, but all the solutions seem to be unnecessarily complicated.</p>
  
  <p>What's a simple solution to this simple problem that would make sense to a beginner?</p>