title: How to calculate the total size of certain files only, recursive, in linux
body: <p>I've got a bunch of files scattered across folders in a layout, e.g.:</p>
  
  <pre><code>dir1/somefile.gif
  dir1/another.mp4
  dir2/video/filename.mp4
  dir2/some.file
  dir2/blahblah.mp4
  </code></pre>
  
  <p>And I need to find the total disk space used for the MP4 files <em>only</em>. This means it's gotta be recursive somehow.</p>
  
  <p>I've looked at <code>du</code> and fiddling with piping things to <code>grep</code> but can't seem to figure out how to calculate just the MP4 files no matter where they are.</p>
  
  <p>A human readable total disk space output is a must too, preferably in GB, if possible?</p>
  
  <p>Any ideas? Thanks</p>