Old geek statement: If you think perl is the answer to a simple filter question then think twice. You might be right, but it's likely smaller faster tools already exist. And I say this as someone who has written 1000 line shell scripts and even bigger perl scripts; perl is good for complicated tasks, but rarely required for simple stuff. Don't wield your hammer because that's all you know.
In this case, everyone who responded with a perl solution needs their hammer taken away.
Heh. The service provider where I worked was a perl shop. I hated perl but that was because I was not familiar with perl and it had way too many modules and what not.
What happens sometimes is that the perl chums will hammer out a solution in perl and use it. Later their perl solution gets converted to awk, bash or C by themselves or by me due to perl being way too expensive.
I say let them keep their hammer and then make them use a more efficient one when they prove their hammer does work.