Question

I’m using a 3rd party ETL tool with some FTP capabilities, but they’re minimal (it’s called Pentaho).

All I need to do is download the most recent file zip off of a ftp site. The site content appears as the following:

...
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

So, in this case, I’d want the tfo.supplement.20120905.zip file.

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.

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.

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?

Answer 1

Are you looking for something like this? >>

s/\s(\d+)\/(\d+)\/(\d{4})\s/{$d = 10000*$3+100*$1+$2 if $d < 10000*$3+100*$1+$2}/eg;

Test this code here.