I know this isn't quite your question, but I'd recommend writing perl code in perl, rather than shell in perl. ;-) For example, use the File::Copy module to copy your file. Otherwise you may as well write this in shell - it would be just a bit simpler that way ;-)

(I know that when I started perl, I didn't know about File::Copy, so thought you may want to know about it - it is standard in all perls I've used that I recall.)