Namazu is a full-text search system intended for easy use. Not only does it work as a small or medium scale Web search engine, but also as a personal search system for email or other files. Supported document types: HTML, Mail/News, MHonArc, RFC, TeX (with detex), man (with groff), Word (with wvWare), PDF (with pdftotext) and plain text.
Net::Z3950::SimpleServer is a Perl module which implements the server side of the Z39.50 (information retrieval) protocol. It hides the complexity of network exchanges, packet serialization, and session handling. You are required only to implement simple callbacks to support searching and record retrieval. It is the basis of the "Zoogle" project, which is a Z39.50 gateway to the Google web index.
PHP Content Management System (phpCMS) makes it possible to need only one template for your whole Web site. It allows you to provide dynamic menus with unlimited levels, and use templates and sub-templates without a database. It is search engine-friendly and proxy-friendly, as the pages it generates can not be distinguished from static HTML pages. PHP code can be added to any template and content file with an optional module. It supports the caching of parsed pages and gzip compression.
SWISH++ is a Unix-based file indexing and searching engine (typically used to index and search files on web sites). It was based on SWISH-E although SWISH++ is a complete rewrite. SWISH++ is at least 10 times faster and can handle much larger numbers of files. Additionally, it has unique features such as selective non-indexing, on-the-fly filters, user-selectable stemming, and more.
libextractor is a library used to extract meta-data from files of arbitrary type. It is designed to use helper-libraries to perform the actual extraction, and to be trivially extendable by linking against external extractors for additional file types. The goal is to provide developers of file-sharing networks, file managers, and WWW-indexing bots with a universal library to obtain meta-data about files. It includes a shell-command and bindings for Java (JNI) and Python.
Dowser is a Web research and archiving tool that clusters results from search engines, associates words that appear in previous searches, and keeps a local cache of all the results you click on in a searchable database along with summaries and links to related information. It helps you to keep track of what you find, with no advertising.
Hyper Estraier is a full-text search system. It can be used as a Web search engine, mailbox searching, etc. It features high performance searching, high scalability of target documents, a perfect recall ratio by the N-gram method, phrase searching, attribute searching, and similarity searching. Multilingualism is supported with Unicode. It is independent of file format and repository, and has a simple and powerful API.