title: Windows: compare files in folders and delete non existent
body: <p>I have huge directories + subdirs containing files on Windows. 
  On the windows command line (or through a script) I'd like to compare two folders and delete files from the subfolder that are not in the main folder.</p>
  
  <p>In the example below the even numbered files should be deleted from the subfolder.</p>
  
  <pre><code>folder: C:\folder1
      file1.jpg
      file3.jpg
      file4.jpg
      file7.jpg
      file9.jpg
  
  subfolder: C:\folder1\RAW\
      file1.CR2
      file2.CR2
      file3.CR2
      file4.CR2
      file5.CR2
      file6.CR2
      file7.CR2
      file8.CR2
      file9.CR2
  </code></pre>
  
  <p>I have tried several scripts I found here, but non of them do the job. Any help is appreciated!</p>