Checks to see if a file or folder exists
The fFile variable determines whether you're
looking for a File (True) or Folder(False)
The strName variable holds the fully qualified
path you're looking For

this function returns the aggregated size
of all files in a directory and its subdirectories

Retrieve information about a file

Check the attributes of a file or folde

Software Requirements:

Crypt_HMAC:
http://pear.php.net/package/Crypt_HMAC
HTTP_REQUEST:
http://pear.php.net/package/HTTP_Request
PEAR:
http://pear.php.net/

Two very usefull functions to have around.

(note: dollarfy requires commify to work)

This php script provides a unique random key with 32 characters and can be used to avoid the system to pass some primary keys across the url, by example.

Function that splits a given string into sections based on the allowed length for a section. Does not split words up. Splits string on Space character (can be set to another character)

Takes a given directory and lists all the files and folders under it, including sub folders. Resulting array contains associative (folders) and indexed (files) elements. Doesn't return "." and ".."

This function takes a directory, and a "folder" search parameter.
If it finds the directory (either in single level, or any sub folder) it will return the relative path of that folder. "FALSE" if not found. Skips over files and "." and ".." directories. Recursive by default.