$  perl -pe 's/^(?=.*utf8)/#/' 1.pl | tee 1.without_utf8.pl
#!/usr/bin/perl -w
use 5.011;
#use utf8;
use Devel::Peek;
my $string = 'Gödel';
Dump($string);
$string = 'über';
Dump($string);
$string = 'alleß';
Dump($string);
$