for (@_) { whatever($_) } is fine, for my $whatever (@_) just helps readability in case the body of the loop grows to more than a few lines long. But one should stay away from my $_.

It wouldn't hurt to upgrade your Perl if you can, 5.10.1 was released over 4 years ago. If you're on a multi-user system perhaps your sysadmin has already installed a newer version of Perl in a non-default location, such as under /opt/.

I see this quite often on PerlMonks and I really don't understand why I see so many "typos when copying"... Ctrl+C, Ctrl+V ???