use Path::Class;
use List::Util qw(first);

my $dir = $ARGV[0] || '.';

my $newest =
    first { $_ }
    sort  { $b->stat->mtime <=> $a->stat->mtime }
    dir($dir)->children;

$newest->is_dir 
    ? say "Neustes Verzeichniss: $newest"
    : say "Neuste Datei: $newest";