sub byfile { my @a = split /(\d+)/, $a; my @b = split /(\d+)/, $b; my $M = @a > @b ? @a : @b; my $res = 0; for (my $i = 0; $i < $M; $i++) { return -1 if ! defined $a[$i]; return 1 if ! defined $b[$i]; if ($a[$i] =~ /\d/) { $res = $a[$i] <=> $b[$i]; } else { $res = $a[$i] cmp $b[$i]; } last if $res; } $res; }