This is the original BSD ex/vi, updated to build and run on modern
Unix systems. Compared to most of its many clones, the original vi is
a rather small program (~120 KB code on i386) just with its extremely
powerful editing interface, but lacking fancy features like multiple
undo, multiple screens or syntax highlighting. In other words, it is a
typical Unix program that does exactly what it should and nothing more.
I intend to preserve this style in maintaining my port, except for
changes to achieve POSIX.2 standards compliance, features in the SVR4
versions of vi, and, of course, bug fixes.

WWW: http://ex-vi.sourceforge.net/