#!/usr/bin/perl -w
use strict;
use Data::Dumper;

sub hashdir {
    my $dir = shift || '.';
    opendir my $dh, $dir or die $!;
    my $tree = {}->{$dir} = {};
    while ( my $file = readdir($dh) ) {
        next if $file =~ m[^\.{1,2}$];
        my $path = $dir . '/' . $file;
        $tree->{$file} = hashdir($path), next if -d $path;
        push @{ $tree->{'.'} }, $file;
    }
    return $tree;
}

my $tree = hashdir(shift);

print Dumper $tree;