title: search a string in a file with case insensitive file name
body: <p>I want to grep for a string in all the files which have a particular patter in their name and is case-insensitive.</p>
  
  <p>For eg if I have two files ABC.txt and aBc.txt, then I want something like</p>
  
  <pre><code>grep -i 'test' *ABC*
  </code></pre>
  
  <p>The above command should look in both the files.</p>