If you want to improve your Perl code read “Modern Perl”. (There is more than one version, and I know the first version was made freely available online)

Perl is a better language for large codebases than most people give it credit for. That said it allows more creativity when it comes to your code. So you can make awful code just as easily as beautiful code. Perl6 makes the beautiful code easier to write and shorter, while making awful code a bit harder to write.

Good news! Every version is freely available online. Here's the most recent:

http://modernperlbooks.com/books/modern_perl_2016/index.html