A PERL script EXPLAINED.

First of all, I'm looking for someone who finished at least 1 project related to perl. I don't need you to write a script for me, all I want is to understand a script I already have. Long story short, a couple of days ago I fired someone who didn't want to work anymore. He was on the phone all day long, but that's not why I'm here. After I fired him, I found a script on two of our computers, and I can't understand why they were there, what they are, and what he used them for. I don't know programming, so what is need is someone who is capable to make me understand the following things: 1) What this script is, how it works and what it does. 2) Could this script produce any kind of damage to the computers I have in my company? (It looks like some kind of merchant or something like this) I THINK THAT'S ALL. Thanks P.S. The script/s is/are SMALL, like 100 lines or something like this.