You posted no Perl code to examine in order for us to help you.
You posted no protocol for 'file uploads' (FTP, SCP, rsync?)
You posted no OS details, you could be trying to copy windows shares or NFS mounts or, well, who knows?
and this?:

Anyone else may avoid wasting everyone else's time, and keep their thoughts to themselves.

Means that you did not read corion's helpful links to the Perl regex tutorial. You don't need a regex, you need to learn the fundamentals of how regex works.

This is a very poorly formed question, you should add more information and read the tutorials provided to you.