This was how (and why) I learned. I needed to be able to interact with an FTP site autonomously. I had heard, I have no idea where, that Perl could do that. I found the doc for Net::FTP and 5-6 examples of how to use it online, and went from there. That solved my immediate problem and also revealed how (relatively) easy learning other language features would be, because of the wealth of tutorials and examples online.
Once I had one working Perl program, that opened the door for others. The next application, IIRC, was compiling statistics over a very large number of text files for a report. I later learned regexes when a trading partner mixed different transaction types in a single transmission and I needed to sort them out. It seemed like magic.
I continue to learn to meet new challenges at work, and also from stuff I pick up here by osmosis. I picked up The Perl 5 Programmer's Reference at Half-Price Books and that sits on my desk; it is usually the first place I look. Perl documentation would be the second.
As an aside, I have that particular book because it was at the store at the same time I was. It is okay for syntax, for 'how' but never for 'why'. I would not recommend it over any other.