title: Grep(or alternative) for 2 strings, matching one, another or both are success, contains anything else is a fail
body: <p>I want to analyse output from a command.
  I have 2 potential string matches.
  If I match one, the other or both, I class that as a pass.
  If the output contains anything else I want to flag it as a fail.</p>
  
  <p>This was my original code, which works most of the time.
  But when the output(on a rare occasion) contains both my strings, which is allowed. It flags as a fail:</p>
  
  <pre><code> if [ "$STATUS" != "Ok" ] &amp;&amp; [ "$STATUS" != "Non-Critical" ]             
     then  
     echo "FAILED: STATUS NOT 'Ok' OR NOT 'Non-Critical'"
     else
     echo " Status check good."
   fi
  </code></pre>
  
  <p>The above fails for me when my output contains both strings, which is not what I want.</p>
  
  <p>So, to be clear:
  Ok - On it's own is a pass.</p>
  
  <p>Non-Critical - On it's own is a pass. </p>
  
  <p>Ok
  Non-Critical - is a pass.</p>
  
  <p>Non-Critical
  Ok - is a pass.</p>
  
  <p>ANYTHING else is a fail</p>
  
  <p>Hoping someone smarter than me can help :-)</p>