title: List files with certain extensions with ls and grep
body: <p>I just want to get the files from the current dir and only output .mp4 .mp3 .exe files nothing else.
  So I thought I could just do this:</p>
  
  <pre><code>ls | grep \.mp4$ | grep \.mp3$ | grep \.exe$
  </code></pre>
  
  <p>But no, as the first grep will output just mp4's therefor the other 2 grep's won't be used.</p>
  
  <p>Any ideas? PS, Running this script on Slow Leopard.</p>