I've been administrating networks for a mere 3 years now, and yet i've through neccesity had to teach myself perl, just because it's so damn useful. Every network administrator will come across occasions where you'll need a custom tool to perform a task. Quite frequently, it's as simple as editing a particular value in a series of text files, and whilst you could use sed/awk, imho it's easier and quicker to knock up some quick perl to do it.

In situations like this, it's not up to your management as to what tool you use to achieve the task, it's a 20 minute job you do as part of your working day. Perl is the king at throwaway code like this, and especially in a *nix environment, is to my mind, indispensable. It's saved me a lot of time, too :)