use strict;
use Benchmark qw(cmpthese);
use vars qw( $x );

$x = 'This-is-a-test-string-I-just-typed-in-for-fun';

cmpthese (-10, {
    'transl' => '$x =~ tr/-/_/; $x =~ tr/_/-/;',
    'regexp' => '$x =~ s/-/_/g; $x =~ s/_/-/g;',
} );