$ perl -E '
    my @x = (23, 12, 45);
    say "Unsorted:";
    say for @x;
    say "Ascending:";
    say for sort { $a <=> $b } @x;
    say "Descending:";
    say for sort { $b <=> $a } @x;
'
Unsorted:
23
12
45
Ascending:
12
23
45
Descending:
45
23
12