There may be an issue with your file system. I just created a directory with 20,000 subdirectories. Then I used the following code to get the name of all directories. It took no (noticeable) time to run: 
use warnings;
use strict;
use autodie;

my $dir = '/tmp';
opendir my ($dh), $dir;
my @dirs = grep { -d "$dir/$_" } readdir $dh;
print scalar(@dirs), "\n";

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In reply to Re: Get folders in a directory with 20k directories? by toolic
in thread Get folders in a directory with 20k directories? by perlpreben

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