The OP is a computer science student, so I'm assuming that he/she/it has a fairly good grounding in programming (possibly an unwarranted assumption based on the horror stories I hear about some CS courses, but that's another issue).

With that and a copy of the llama book, I suggest finding a little project where you need some code, then find some perl code somewhere on tha intarweb that claims to do the job, and then learn perl by fixing that code because it's invariably going to be buggy (with insecure being a subset of 'buggy') and/or not a perfect fit for your task. I learnt perl by downloading some of Matt Wright's scripts and fixing their most obvious bugs. This might be a useful exercise, even though there is now the bugfixed NMS versions of them.

IMO, perl code is correct if:

• it works (and you know it works cos you've tested it)
• it is documented
• someone else can understand it

which is exactly the same standard I would apply to code written in any other language.