#! /usr/local/bin/perl -w

use strict;

sub  forward ($$) {my ($x, $y) = @_; $x cmp $y}
sub backward ($$) {my ($x, $y) = @_; $y cmp $x}
sub    bylen ($$) {my ($x, $y) = @_;
    length($x) <=> length($y) || $x cmp $y
}

my @sorter = qw(forward backward bylen);

my @list = qw(kholsky stencil dnubietna barkhausen
    manganese fairing fleische flake schlozhauer gascoigne);

my $s = $sorter[shift || 0];
print "$_\n" for sort $s @list;