my $datestring = "2003/11/19";  # input

use Time::Local;
my($y, $m, $d) = $datestring =~ m<^(\d+)/(\d+)/(\d+)$>
  or die "Not a valid date";
my $time = timegm(0, 0, 12, $d, $m-1, $y);
print "The time value is $time, for " . gmtime($time) . "\n";