I usually try to recursively read directory content. This script will print to STDOUT each subdirectory and files in each subdirectory of your chosen directory:

#!/usr/bin/perl

use strict;
use warnings;

my $dir = '/usr/lib/perl5/5.8.8/CGI';

@ARGV = $dir unless @ARGV;
use File::Find;
find sub { print $File::Find::name, -d &&  $dir, "\n" }, @ARGV;
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Note that neither opendir, readdir, nor File::Find will print the "contents" of the files, just the names thereof.