title: move and number files with same name in a new directory
body: <p>I have a directory with (a lot of) subdirs of the type </p>
  
  <pre><code>td.0000000
  td.0000050
  td.0000100
  etc.
  </code></pre>
  
  <p>in each subdir I have a file called "density.cube"</p>
  
  <p>I would like to move all the "density.cube" in a new subdir "td"</p>
  
  <pre><code>td/density0000000.cube
  td/density0000050.cube
  td/density0000100.cube
  etc.
  </code></pre>
  
  <p>or at least</p>
  
  <pre><code>td/density.cube0000000
  td/density.cube0000050
  td/density.cube0000100
  etc.
  </code></pre>
  
  <p>How could I achieve that ? I have basis in bash and python but it is obviously not enough...</p>
  
  <p>thanks !</p>