I'm trying to implement what you posted but I'm pretty lost: what is "$fake"? what is this code supposed to do? Thanks for all your help!

$fake is a filehandle , there is no physical file, its an in-memory file, so I called it $fake

What this code does is demonstrate how to trap warnings by making them fatal, so that you can print out the current line of the file

It does this by promoting warn to die which is caught with eval

Its an answer to your question