htdig binary package in Ubuntu Xenial amd64

 The ht://Dig system is a complete web search engine for a small
 domain or intranet. It is not meant to replace the major
 Internet-wide search engines; instead it is meant to cover the search
 needs of a single company, campus, or even a particular subsection of
 a website.
 .
 Features:
  - intranet searching, spanning multiple local web servers;
  - robot exclusion;
  - boolean expression searches;
  - configurable search results;
  - fuzzy searching (various algorithms supported);
  - indexing of HTML and text files;
  - keyword tagging of HTML documents;
  - email notification of expired documents;
  - indexing of protected servers;
  - searches on subsections of the database;
  - limitation of search depth;
  - ISO-Latin-1 character set support.

Source package