Here is a tip for you, skip anything talking about readdir and glob, start by learning File::Find::Rule and Path::Tiny
examples
Re: ExtUtils::Command touch (Path::Tiny , Shell::Command )
Re^2: Broken Function ( Path::Tiny spew )
Re: Windows - dirname(__FILE__) ( Path::Tiny::path(__FILE__)->realpath->parent
Re^2: getting picky with File::Find::Rule less typing find/rule
Re: I humbly ask for your help with parsing (Path::Tiny/File::Find::Rule)
Re: File::Find: Return array of "wanted" files (File::Find::Rule)

Also, get a copy of Modern Perl by chromatic a loose description of how experienced and effective Perl 5 programmers work....You can learn this too.

It is reviewed and recommended by Perl Tutorial Hub