How to display all folders and subfolders of unlimited nesting in PHP?

Question

PHP

How to display all folders and subfolders of unlimited nesting in PHP?
Example:

Папка
-Папка1
--Папка2
Папка3

Preferably with SPL

Answer 1

www.php.net/manual/en/class.recursivedirectoryiter...
stackoverflow.com/questions/20045622/php-recursive...

Answer 2

glob

Answer 3

exec("find /etc -type d", $out); 
print_r( $out );