use Time::Local timelocal;
my ($m,$d,$y,$t);
do
{
    my ($date);
    print "date (MM-DD-YY) ? ";
    $date=<>;
    chomp($date);
    ($m,$d,$y)=split(/-/,$date); 
    $m -= 1;
    $y += 1900;
    $t = eval "timelocal(0,0,0,$d,$m,$y)";
}
until (!$t);