DIRB IS a Web Content Scanner. It looks for existing (and/or hidden) Web Objects. It basically works by launching a dictionary basesd attack against a web server and analizing the response.
dirb
-a <agent_string> Specify your custom USER_AGENT. (Default is: "Mozilla/4.0
(compatible; MSIE 6.0; Windows NT 5.1)")
-b Don't squash or merge sequences of /../ or /./ in the given URL.
-c <cookie_string>
Set a cookie for the HTTP request.
-E <certificate>
Use the specified client certificate file.
-f Fine tunning of NOT_FOUND (404) detection.
-H <header_string>
Add a custom header to the HTTP request.
-i Use case-insensitive Search.
-l Print "Location" header when found.
-N <nf_code>
Ignore responses with this HTTP code.
-o <output_file>
Save output to disk.
-p <proxy[:port]>
Use this proxy. (Default port is 1080)
-P <proxy_username:proxy_password>
Proxy Authentication.
-r Don't Search Recursively.
-R Interactive Recursion. (Ask in which directories you want to scan)
-S Silent Mode. Don't show tested words. (For dumb terminals)
-t Don't force an ending '/' on URLs.
-u <username:password>
Username and password to use.
-v Show Also Not Existent Pages.
-w Don't Stop on WARNING messages.
-x <extensions_file>
Amplify search with the extensions on this file.
-X <extensions>
Amplify search with this extensions.
-z <milisecs>
Amplify search with this extensions.