$source =~ s/$map{$key}/$key/g;

##</code><code>##

       $source =~ s/\Q$map{$key}/$key/g;

##</code><code>##

    for my $line (@source) {
        chomp $line;
        my $tmpline = '';
        for my $key (split //, $line) {
            $tmpline .= $map{$key};
        }
        print "$tmpline\n";
    }