I like your script for its simplicity if one wants a quick answer to what lines differ.
in reply to Poor man's diff
Having read that you don't have Cygwin installed, I strongly recommend that you or anybody else does so. Or install GNU utilities for Win32. Once you start to think that you need to write these types of scripts, it would be worth it to install Cygwin. It has saved me countless hours of trying to write my own stuff that already exists on a *nix system.
I write this because my hope is that it will help many others too.
unashamed Cygwin advocate