vi 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.
Nie Alarie added nvi 2.1.3 to pkgsrc in June.
nvi is a distinct branch of vi, not to be confused with Vim or its offshoots. You can install Vim from ports—and I do—but nvi is the default editor family in the BSDs, so its useful to be sufficiently proficient in it. You may find learning nvi helps you be a better Vim user, too.
I taught myself nvi while I was at uni in 2010, which I’ve just realised is a decade ago. Aiyo.