DokuWiki is a standards-compliant, simple-to-use Wiki mainly aimed at creating documentation of any kind. It is targeted at developer teams, workgroups, and small companies. It has a simple but powerful syntax which makes sure the datafiles remain readable outside the Wiki, and eases the creation of structured texts. All data is stored in plain text files, so no database is needed
LyX is a document processor that encourages an approach to writing based on the structure of your documents, not their appearance. It is intended for people people who write and want their writing to look great without tinkering with formatting details, font attributes, or page boundaries. On screen, it looks like any word processor, but it uses the TeX engine for printed output and producing richly cross-referenced PDFs. It is stable and fully featured.
GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
DocBook is an XML vocabulary which enables you to create document content in a presentation-neutral form that captures the logical structure of the content. Using the DocBook Project XSL stylesheets, you can publish DocBook content as HTML pages and PDF files and other formats, including man pages, HTML Help, and JavaHelp.
tex-upmethodology provides a complete set of LaTeX styles that permit you to write documents according to a UP-based methodology. Its major features are document history, task management, design and specification documentation, and helping tools. tex-upmethodology is officially supported by CTAN.
Txt2tags converts a text file with minimal markup to HTML, XHTML, SGML, DocBook, LaTeX, Lout, Man page, Creole, Wikipedia, Google Code Wiki, PmWiki, DokuWiki, MoinMoin, MagicPoint, PageMaker, AsciiDoc, or ASCII Art. It is simple and fast and features automatic TOC, macros, filters, include, tools, GUI, CLI, and Web interfaces, translations, and extensive documentation.
The ManEdit UNIX Manual Page Editor is an editor specifically tailored for UNIX manual pages. It has a preview viewer, uses the manual page XML format for easy editing, and comes with a tutorial and reference guide. It uses the GTK+ widget set and features syntax highlighting, a complete drag and drop system for easy viewing and editing, a crash recovery system, and sample manual page templates.
doclifter helps with lifting documents with nroff markup to XML-DocBook. Lifting documents from presentation level to semantic level is hard, and a really good job requires human polishing. This tool aims to do everything that can be mechanized, and to preserve any troff-level information that might have structural implications in XML comments. TBL tables are translated into DocBook table markup, PIC into SVG, and EQN into MathML (relying on pic2svg and GNU eqn for the last two).