Emacs

Emacs (/ˈiːmæks/ ^ⓘ), originally named EMACS (an acronym for "Editor Macros"),^[1][2][3] is a family of text editors that are characterized by their extensibility.^[4] The manual for the most widely used variant,^[5] GNU Emacs, describes it as "the extensible, customizable, self-documenting, real-time display editor".^[6] Development of the first Emacs began in the mid-1970s,^[7][8] and work on GNU Emacs, directly descended from the original, is ongoing; its latest version is 29.4^[9] , released June 2024.

Emacs has over 10,000 built-in commands and its user interface allows the user to combine these commands into macros to automate work. Implementations of Emacs typically feature a dialect of the Lisp programming language, allowing users and developers to write new commands and applications for the editor. Extensions have been written to, among other things, manage files, remote access,^[10] e-mail, outlines, multimedia, Git integration, RSS feeds,^[11] and collaborative editing,^[12] as well as implementations of ELIZA, Pong, Conway's Life, Snake, Dunnet, and Tetris.^[13]

The original EMACS was written in 1976 by David A. Moon and Guy L. Steele Jr. as a set of macros for the TECO editor.^{[14][1][2][3][15]} It was inspired by the ideas of the TECO-macro editors TECMAC and TMACS.^[16]

The most popular, and most ported, version of Emacs is GNU Emacs, which was created by Richard Stallman for the GNU Project.^[17] XEmacs is a variant that branched from GNU Emacs in 1991. GNU Emacs and XEmacs use similar Lisp dialects and are, for the most part, compatible with each other. XEmacs development is inactive.

GNU Emacs is, along with vi, one of the two main contenders in the traditional editor wars of Unix culture. GNU Emacs is among the oldest free and open source projects still under development.^[18]