use strict;
use Data::Dumper;

my %hash = (
  'Hello ' => 'world',
  'The'  => 'world ',
);

print Dumper \%hash;

##</code><code>##

for (keys %bad_hash) {
    if ($bad_hash{$_} =~ /orl/) { # because we're looking for "hello"
        $hash{ $_ } = $bad_hash{ $_ }
    }
}

print Dumper \%bad_hash;