nvi is an implementation of the ex/vi text editor.

The original vi was written by William Joy. Later Mark Horton added
a number of enhancements.

nvi was written by Keith Bostic and was distributed as part of the
Fourth Berkeley Software Distribution (4BSD) by the University of
California, Berkeley.

This version is based on a fork of nvi by Sven Verdoolaege. It is
very similar to the base vi but includes the expandtab option from
NetBSD which is handy for Python development.