GNU Emacs is an extensible, customizable, free/libre text editor. 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-aware editing modes, including syntax coloring, for many file types - complete built-in documentation, including a tutorial for new users - full Unicode support for nearly all human scripts - powerful customizability, using Emacs Lisp code or a graphical interface - a vast ecosystem of functionality beyond text editing, including a project planner, mail and news reader, debugger interface, calendar, even a psychotherapist, and more - a packaging system for downloading and installing extensions. WWW: https://www.gnu.org/software/emacs/