Emacs is an extensible, customizable text editor developed by GNU. GNU was launched in 1983 with the mission of developing a unix-compatible system that would offer 100% free software - Emacs is one of these applications. Emacs is compatible with Mac OS X and Microsoft Windows operating system. Emacs provides a content-sensitive editing mode that is equipped with syntax colouring to aid users in identifying different components and file types. Emacs caters to a variety of users: providing tutorials for beginners and allowing customization for more advanced encoders. With full Unicode support and a "large number of extensions that add other functionality", Emacs is a stellar free editing system.