title: Complex regex - Find most recent date in list
body: <p>I'm using a 3rd party ETL tool with some FTP capabilities, but they're minimal (it's called Pentaho).</p>
  
  <p>All I need to do is download the most recent file zip off of a ftp site.  The site content appears as the following:</p>
  
  <pre><code>...
  File:tfo.supplement.20120901.done   9/1/2012    3:48:00 AM
  File:tfo.supplement.20120901.zip    421144 KB   9/1/2012    3:48:00 AM
  File:tfo.supplement.20120904.done   9/4/2012    3:57:00 AM
  File:tfo.supplement.20120904.zip    421794 KB   9/4/2012    3:57:00 AM
  File:tfo.supplement.20120905.done   9/5/2012    3:28:00 AM
  File:tfo.supplement.20120905.zip    421875 KB   9/5/2012    3:28:00 AM
  </code></pre>
  
  <p>So, in this case, I'd want the tfo.supplement.20120905.zip file.</p>
  
  <p>The 3rd party tool only provides a get-file option that takes a folder and a regular expression.  It will grab all files in the target FTP site folder matching the regular expression.</p>
  
  <p>Someone told me that it is possible to make a regex that will actually compare the different matching options and output the maximum one. E.g. take all tfo.supplement.* files ending in .zip and treat the date in the middle as an integer, pick the one with the largest integer.</p>
  
  <p>I had no idea regex could support that kind of functionality.  Can someone help me build an expression I can use in this use case?</p>