If you are fishing for email addresses within a string, then take a look at Email::Find and Email::Valid. As holli pointed out, a use strict; use warnings; statement would have caught that. However, this is a another method of fishing for emails.

use strict;
use warnings;
use Email::Find;
 my @emails;
 my $string = "dummy\@dumdum.com";
 my $finder = Email::Find->new(sub {
       my ($email, $orig_email) = @_;
       my $escaped = $email->format;
       $escaped =~ s/@/\\\@/;
       push @emails, $escaped;
       return $orig_email;
       });
 $finder->find(\$string);
 print @emails;

__OUTPUT__

dummy\@dumdum.com
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