#!/usr/bin/perl
use warnings;
use strict;

my $p = $ARGV[0] || "/";

for (;;) {
    opendir(D, $p);
    my @f = grep {! /^\.\.?$/ } readdir(D);
    close(D);
    if (!@f) {
	# empty or unreadable directory
	print "$p\n";
	exit(0);
    } 
    my $f = $f[rand($#f + 1)];
    $p = "$p/$f";
    if (! -d $p) {
	print "$p\n";
	exit(0);
    } 
}