Nvi
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- The correct title of this article is nvi. The initial letter is shown capitalized due to technical restrictions.
nvi (new vi) is a re-implementation of the classic Berkeley text editor, ex/vi, traditionally distributed with BSD, and later, Unix systems. It was originally distributed as part of the Fourth Berkeley Software Distribution (4BSD).
Due to licensing disputes between AT&T and the Computer Systems Research Group at the University of California, Berkeley (see USL v. BSDi), the CSRG was required to the replace Unix-derived portions of BSD source with new and unencumbered code. nvi was one of many components to be re-written despite the fact that even the original vi was from UC Berkeley. AT&T had a legal claim over the license. nvi turned out to be a major improvement over the classical vi as discussed below.
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[edit] Features
Usually referred to as a vi-clone, nvi contains a number of features not present in the original program. These include:
- 8-bit clean data, lines and files limited by available memory
- Multiple edit buffers
- Colon command-line editing and path name completion
- Tag stacks
- Cscope support
- Extended Regular Expressions
- Infinite undo
- Horizontal scrolling
- Preliminary support for Perl and Tcl/Tk scripting languages
[edit] Credits and distribution
nvi was written by Keith Bostic, and currently seems to be frozen at version 1.79. It is the default vi on all BSD systems (NetBSD, OpenBSD, and FreeBSD).
Sven Verdoolaege has been developing a GTK+ front-end for nvi, but this effort seems to have stalled. The aspects of nvi that are still marked preliminary or unimplemented are, for the time being, likely to remain that way.
Due to the liberal policy of the BSD license, nvi can vary subtly across the BSDs. It was originally derived from the first incarnation of elvis, written by Steve Kirkendall.
As with the original vi, nvi is only executable on POSIX/Unix platforms due to its reliance on the curses/ncurses library.
