sub next_friday {

my $now = shift || time();
my ($sec,$min,$hour,$mday,$mon,$year,$wday,$rest) = localtime($now);

my $then = (($wday-5) * 60 * 60 * 24);
($sec,$min,$hour,$mday,$mon,$year,$rest) = localtime($now - $then);

$mon += 1;
$year += 1900;

return "$year.$mon.$mday";

}