use Net::SMTP;

    $smtp = Net::SMTP->new('mailhost');

    $smtp->mail($ENV{USER});
    $smtp->to('postmaster');

    $smtp->data();
    $smtp->datasend("To: postmaster\n");
    $smtp->datasend("\n");
    $smtp->datasend("A simple test message\n");
    $smtp->dataend();

    $smtp->quit;