The code itself looks fine.

PBP will tell you to:

• Use for instead of foreach
• Leave out the parentheses from functions, e.g. use split /,/, $_ instead of split(/,/,$_)
• And use msx on your regexes

Update: You should have use strict; and use warnings; at the top of your code. I realise this is just a code fragment and you may have those lines in the complete script - but you did ask :-)