I have a file named "change_directoryName.php".
There is a directory named "old_directoryName" in the directory.
I like to put some code into the file "change_directoryName.php" for changing the directory name from "old_directoryName" to "new_directoryName".
The would-be code below doesn't work correctly, but I hope it shows what I want to try,
It may benefit you to search php.net before posting :)
The PHP documentation has a full list of all the filesystem functions.