4.4BSD re-implementation of vi

 Vi is the original screen based text editor for Unix systems.
 It is considered the standard text editor, and is available on
 almost all Unix systems.
 .
 Nvi is intended as a "bug-for-bug compatible" clone of the original
 BSD vi editor. As such, it doesn't have a lot of snazzy features as do
 some of the other vi clones such as elvis and vim. However, if all
 you want is vi, this is the one to get.