In the words of its official website ht://Dig is "a complete world wide web indexing and searching system for a domain or intranet...meant to cover the search needs for a single company, campus, or even a particular sub section of a web site." ht://Dig was originally developed at San Diego State University, and is today very popular amongst developers looking to quickly add search engine capabilities to a Web site.

ht://Dig works by traversing a Web site and creating a database of all the unique words it finds as it follows hyperlinks from one page to another. This database, together with information on the URL associated with each document, is created every time you request a re-indexing of the site, and is merged with the results of previous index runs to create the foundation for the search engine.

Every time a search is executed, this database is scanned for matches to the search string and a list of results retrieved. The matches are further ranked according to an internal scoring system to filter down to the most relevant, and the results returned to the user, together with links to the pages on which the matches occurred. The process, though somewhat complicated, is nonetheless extremely fast and -- thanks to intelligent search algorithms and scoring systems -- also very accurate.

ht://Dig also supports Boolean searches, which make it possible to selectively widen or close a search; fuzzy searching, in which the search is automatically expanded to include similar-sounding words, synonyms and plurals; depth-limited searching, in which only documents which are at a particular depth from the tree root are searched; and META-tag indexing for more accurate search results. Both search and result pages can be extensively customized in the ht://Dig system, and -- since the source code is freely available under the GPL --developers can even modify and enhance the application to their own specific needs.

Now that you have the background - let's get to work, by installing and configuring ht://Dig.