my @numbers = (15,5,7,3,9,1,20,13,9,8,15,16,2,6,12,90);
my @a = sort {$a <=> $b} @numbers;
print join(",",@a), "\n";
print $a[-2], "\n";

__END__

1,2,3,5,6,7,8,9,9,12,13,15,15,16,20,90
20