Slackermedia
The Workflow Edition
Libre Office
The all-in-one solution for the serious author. Open file formats to protect your data's portability, intuitive layout and formatting, and a familiar interface.
Trelby
Sublime screenplay formatting, with no license required. Never be locked out of your own screenplay again. Contains a character name database, scene reporting, and robust importing from other popular screenplay apps.
Advanced Typesetting
Raw text processing is something Unix has been doing since 1970s. Whether you want to write a streenplay, a novel, a technical paper, a mathematical lecture, or some combination of all the above, tools like Docbook, Emacs, Sphinx, LaTex, Lyx, and more are ready to turn your ascii into typesetting art.
and much more.