title: Renaming files in multiple subfolders
body: <p>I have 100 folders that are incremental. E.g.</p>
  
  <pre><code>'20D, 0.5B001'...'20D, 0.5B002'
  </code></pre>
  
  <p>...all the way to </p>
  
  <pre><code>'20D, 0.5B100'
  </code></pre>
  
  <p>Each of those folders contains files that have the same incremental names. E.g. <code>'Test_C1S0002001'...'Test_C1S0002002'</code> etc. </p>
  
  <p>I want to rename every file in each of these folders to <code>'002001'</code> I.e. just get rid of <code>'Test_C1S0'</code> in every one of these subfolders. How can I do this? </p>