Scandir() is a neat function that takes a minimum of one parameter with an optional second. Parameter one is the path of a directory you want to work with - scandir() returns an array of all files and directories in the directory you specify here. Parameter two, if included and set to 1, will sort the array returned reverse alphabetically - if it is not set, the array is returned sorted alphabetically.
This next script prints out a list of all the files and directories in the current directory, with reverse sorting:
$files=scandir(".",1); var_dump($files); ?>
Using scandir() is a quick alternative to calling readdir() repeatedly, and is particularly helpful when you use the second parameter.