I don't care whether he used regular expressions or not. I also don't care whether his Perl looks like C or not. The question that really matters is: is this good Perl? And I'd say it's not:
- He didn't use
use strict
- He didn't enable warnings.
- He's using the old-fashioned two-argument version of open.
- The "open file" comment hurts and gives me the impression that code he usually writes doesn't contain any comments.
- The code is hard to maintain
- Was he allowed to use CPAN modules? A good Perl programmer would look at that option first.