UNIX / Linux Desktop Full Text Search Engine

Recoll is a personal full text search tool for Unix/Linux operating system. It is based upon Xapian which is an Open Source Search Engine Library, released under the GPL.

From the article:

Desktop search engines are all the rage these days. While Beagle may be the most popular desktop search engine for Linux, there are alternatives. If you are looking for a lightweight and easy-to-use yet powerful desktop search engine, you might want to try Recoll. Unlike Beagle, Recoll doesn't require Mono, it's fast, and it's highly configurable. Recoll is based on Xapian, a mature open source search engine library that supports advanced features such as phrase and proximity search, relevance feedback, document categorization, boolean queries, and wildcard search.
Recoll can handle plain text, HTML, OpenOffice.org documents, Mozilla Thunderbird and Evolution email messages, and Lyx and Scribus files. In addition to those native formats, Recoll can also work with other file types by using external helper applications. For example, the Xpdf software provides support for PDF files, while Word, PowerPoint and Excel documents are handled by Antiword and catdoc.

Overall it looks a good search tool for UNIX and Linux oses. You can also try out beagle - a desktop search service for Linux desktop system.