If you run some kind of *nix and you just want to know the answer, it's probably quicker to use the existing tools rather than write a new one.

user@machine:~/src$ find . -name "*.p[lm]" -exec grep -h "^use\|requir
+e" {} + | sort |uniq
use strict;
use Template;
use v5.10;
use warnings;
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