Recoll is a personal full text search package. It is based on a very
strong backend (Xapian), for which it provides an easy to use and
feature-rich interface.

Features:
    * Free, GPL license.
    * Easy installation, few dependancies. No database daemon, web server,
      desktop environment or exotic language necessary.
    * Will run on most Unix-based systems
    * Qt 4 GUI, plus command line.
    * Searches most common document types, emails and their attachments.
      Transparently handles decompression (gzip, bzip2).
    * Powerful query facilities, with boolean searches, phrases, proximity,
      wildcards, filter on file types and directory tree.
    * Multi-language and multi-character set with Unicode based internals.
    * Extensive documentation, with a complete user manual and manual pages
      for each command.

WWW: http://www.lesbonscomptes.com/recoll/