-[omega](http://xapian.org/docs/omega/overview.html) frontend,
-and the [[cpan Search::Xapian]] perl module. (The [[cpan HTML::Scrubber]]
-perl module will also be used, if available.)
+[omega](http://xapian.org/docs/omega/overview.html) frontend, and the
+[[!cpan Search::Xapian]], [[!cpan Digest::SHA]], and [[!cpan HTML::Scrubber]]
+perl modules (on debian, check that you have packages `xapian-omega`, `libsearch-xapian-perl`, `libdigest-sha-perl` and `libhtml-scrubber-perl` installed).
+
+The [[ikiwiki/searching]] page describes how to write search queries.