I agree with Hofmator here. use diagnostics is a very good idea ... for a person still learning Perl. For those of us who've been with it hardcore for over a year, the extra verbiage isn't worth the extra execution time. (And extra RAM, though that's usually less of an issue.)

I would add use 5.6.0; to that list. This makes sure that our and other nifty-pretties from 5.6.0+ are supported. If they're not, you'll know immediately why.

My header almost always looks like:

use 5.6.0;
use strict;
use warnings;
[download]

Then, I can always comment out warnings, if I wanted to.

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/me wants to be the brightest bulb in the chandelier!