GNU Emacs is an extensible, customizable text editor - and more.
At its core is an interpreter for Emacs Lisp, a dialect of the Lisp
programming language with extensions to support text editing.
The features of GNU Emacs include:
- Content-sensitive editing modes, including syntax coloring, for
a wide-range of file types
- Complete built-in documentation, including a tutorial for new users
- Full Unicode support for nearly all human languages and their scripts
- Highly customizable, using Emacs Lisp code or a graphical interface
- Includes a project planner, mail and news reader, debugger
interface, calendar, and more