my $recipient = "root";
unless (defined($recipient)) { $recipient = "root" } # useless

##</code><code>##

$recipient = "root" unless (defined($recipient));

##</code><code>##

substr($message{detail}, 32, 8) =~ /(\w\w)(\w\w)(\w\w)(\w\w)/;
$message{mml} = pack ("CCCC", hex($1), hex($2), hex($3), hex($4));

# simply
$message{mml} = pack ("H*", substr($message{detail}, 32, 8));