I have this set to do both files and directories. To do just directories, then do 'directories-only' => 1 and 'all' => 0. You'll need Filesys::Tree.

#!/usr/bin/perl

use strict;
use warnings;
use YAML;
use YAML::Dumper;
use Filesys::Tree qw/tree/;

my $tree = tree( { 'all' => 1,
                   'max-depth' => 10,
                   'directories-only' => 0,
                   'full' => 1 
}, '/usr/lib' );

my $dumper = YAML::Dumper->new;
$dumper->indent_width(1);
print $dumper->dump({dump => $tree});
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