my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(t
+ime);
my $shour = ($hour > 11 ? $hour - 12 : $hour);
$shour = 12 if ! $shour; # if 0 should be 12
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No point doing extra work computing AM/PM if you don't need them, and if you do, it's easy to determine AM/PM by comparing $hour and $shour. Or if all you want is the hour and you don't care about the rest at all:

my $hour = int (time / 3600) % 12;
$hour = 12 if ! $hour; # if 0 should be 12
[download]