Why we are using " if (($fname != '.') && ($fname != '..')) " in this code... 
Is using to find the file format is Windows or linux or mac ?

```
if (is_dir( "{$dir}/{$fname}" )) {
           if (($fname != '.') && ($fname != '..')) {
                echo "<u>Deleting Files in the Directory</u>: {$dir}/{$fname} <br />";
          deleteDir("$dir/$fname");
             }
 }

```