(PHP 5 >= 5.3.0)
Iterates through a file system in a similar fashion to glob().
$path
   [, int $flags = FilesystemIterator::KEY_AS_PATHNAME | FilesystemIterator::CURRENT_AS_FILEINFO
  ] )$path
   [, int $flags = FilesystemIterator::KEY_AS_PATHNAME | FilesystemIterator::CURRENT_AS_FILEINFO | FilesystemIterator::SKIP_DOTS
  ] )