G'day nathaniels,

I thought I'd draw your attention to the caveats regarding both $` and $'. In perlvar: Variables related to regular expressions, you'll see the same warning for both of these special variables:

"The use of this variable anywhere in a program imposes a considerable performance penalty on all regular expression matches."

The documentation shows alternatives. Do note which Perl versions those alternatives are available in: e.g. @- was added in v5.6.0 while ${^PREMATCH} was added in v5.10.0. And, if you wish, you can use Benchmark to compare them.