Vi

vi is a screen-oriented text editor computer program written by Bill Joy in 1976 for an early BSD release.

vi derivatives and clones

• vi is a port of the classic BSD vi 3.7 to modern Unix systems. It uses ed as a codebase, which is BSD-style free since January 2002. http://ex-vi.sourceforge.net/
• nvi is an implementation of the ex/vi text editor originally distributed as part of the Fourth Berkeley Software Distribution(4BSD). This is the version of vi that is shipped with all BSD-based open source distributions. It has many improvements over the classical vi, including command history and editing, filename completions, multiple edit buffers, multi-windowing (including multiple windows on the same edit buffer) and many more. Other than the improvements, it is more or less the same as the classical vi in terms of look and feel. It is small and fast and blends quite naturally with the unix environment.
• Elvis is a free vi clone for Unix and other operating systems.
• Vigor the popular Unix editor vi with the addition of the Vigor Assistant, a deliberately irritating animated character modelled on Microsoft Office's Clippy.http://vigor.sourceforge.net/
• VILE
• Vim "Vi IMproved" is an updated and extended modal editor, considered by many to be roughly equivalent in editing power to Emacs.
• bvi "Binary VI" is an editor for binary files based on the vi text editor.http://bvi.sourceforge.net/
• svicc is a small VI Clone for the Commodore (64) http://www.floodgap.com/retrotech/cbm/svicc/