Extension:InterwikiRegex

The InterwikiRegex extension adds regex capability for interwiki links. Or something like regex; actually, it's str_replace.

Installation

 * Create a folder in the extensions folder named InterwikiRegex
 * Move the files to the  folder
 * Edit  in the root of your MediaWiki installation, and add the following line near the bottom:

Configuration settings
// Array of interwiki prefixes and the string replacements $wgInterwikiRegexString = array (       'urbandictionary' => array ( ' ' => '+',               '_' => '+',        ) ); This will cause   to link to http://www.urbandictionary.com/define.php?term=would+of, once you have added the appropriate interwiki link using Special:Interwiki.