GNU Emacs is an extensible, customizable text editor. Begun in the mid-1970s as TECO, it was re-written using C and Emacs Lisp to provide portability and an extendable interface. It continues to be actively developed today.
Emacs provides context-sensitive editing modes with syntax coloring, is self documenting, has full Unicode support and extensions to do almost anything. Die-hard Emacs users do most everything from within Emacs: write, compile, run and debug code; read/compose email; browse the web; do project planning etc.
- A paper by Richard Stallman describing the design of Emacs
- The Emacs Wiki, a collaborative wiki for extensions to Emacs
- Wikipedia's Emacs page
- History of Emacs and GPL
- GNU Emacs homepage