For starters, you don't check if open() actually worked. That's not good. You should also use strict; and use warnings; too.

You should also use a consistent coding and indenting style. Doing so will help you see the logic flow of your own code. perltidy can help you with that.

This may sound like i'm picking out the "unimportant" parts of software design. Well, actually, no i'm not. First you have to get the basics right. Then, the tools you use can actually help you in developing your script by telling you about certain problems you might have overlooked.