Htgrep
Htgrep is a CGI script written in Perl that allows you to query any document accessible to your HTTP server on a paragraph-by-paragraph basis. Htgrep is a generic front-end to htgrep.pl, a Perl package that makes it relatively easy to implement simple search engines for the WWW. Htgrep allows you to pass all parameters to the search package as part of the URL, so a forms interface can be used to set the parameters.