This is the README for nex/nvi, a freely redistributable implementation
of the ex/vi text editors originally distributed as part of the Fourth
Berkeley Software Distribution (4BSD), by the University of California,
Berkeley.  
The source code for nex/nvi can be retrieved by using anonymous ftp to
ftp.cs.berkeley.edu.  The file ucb/4bsd/nvi.tar.gz is the gzip'd archive,
of version 1.71 of nex/nvi.  This version is believed to be stable and
problem free.  The file ucb/4bsd/nvi-###.ALPHA.tar.gz is a gzip'd archive
of the current alpha-test release of nex/nvi.  This version reflects the
current development tree, and will be more likely to have problems.  
See the file:
```conf
build/README	for information on building nvi.
LAYOUT		for a description of where everything is.
LICENSE		for the copyright and redistribution terms.
```

If you have any questions about nex/nvi, problems with it, or concerns
about the conditions for redistribution, please contact me:
```conf
Keith Bostic	+1-508-287-4781
394 E. Riding Dr.	bostic@bostic.com
Carlisle, MA 01741
USA
```

##
* This software is several years old and is the product of many folks' work.  
	This software was originally derived from software contributed to
	the University of California, Berkeley by Steve Kirkendall, the
	author of the vi clone elvis.  Without his work, this work would
	have been far more difficult.
	IEEE POSIX 1003.2 style regular expression support is courtesy of
	Henry Spencer, for which I am *very* grateful.
	Elan Amir did the original 4BSD curses work that made it possible
	to support a full-screen editor using curses.
	George Neville-Neil added the Tcl interpreter, and the initial
	interpreter design was his.
	Sven Verdoolaege added the Perl interpreter.
	Rob Mayoff provided the original Cscope support.
	
* Many, many people suggested enhancements, and provided bug reports and
  testing, far too many to individually thank.
  
* From the original vi acknowledgements, by William Joy and Mark Horton:  
	Bruce Englar encouraged the early development of this display
	editor.  Peter Kessler helped bring sanity to version 2's
	command layout.  Bill Joy wrote versions 1 and 2.0 through 2.7,
	and created the framework that users see in the present editor.
	Mark Horton added macros and other features and made the editor
	work on a large number of terminals and Unix systems.
	
* And...  
	The financial support of UUNET Communications Services is gratefully
	acknowledged.
	
##
* Status:
	This software is in beta test, and it's pretty stable.  Almost all of the
	historic functionality in ex/vi is there, the only major missing pieces
	are open mode and the lisp edit option.  
	Nvi is largely 8-bit clean.  This isn't difficult to fix, and was left in
	during initial development to keep things simple.  Wide character support
	will be integrated at the same time that it is made fully 8-bit clean.  
	There aren't a lot of new features in nex/nvi, but there are a few things
	you might like.  The "Additional Features" section of the reference work
	(docs/USD.doc/vi.ref/vi.ref.txt, docs/USD.doc/vi.ref/vi.ref.ps) has more
	information.

##
* Debugging:
	Code fixes are greatly appreciated, of course, but if you can't provide
	them, please email me as much information as you can as to how I might
	reproduce the bug, and I'll try to fix it locally.  Stack traces of core
	dumps are only rarely helpful -- an example file with a set of keystrokes
	that causes the problem is almost invariably necessary.  I know it's
	annoying, but simply playing with the bug until you can reproduce it at
	will, with minimal keystrokes, is immensely helpful to me.  
	Please include the following in the bug report;

	* The version of nvi you're running (use :version to get it).
	* The row/column dimensions of the screen (80 x 32).
	* Unless you're confident that they're not part of the problem,
	  your startup files (.exrc, .nexrc) and the environment variable
	  (EXINIT, NEXINIT) values.  (Cutting and pasting the output
	  of ":set all" is usually sufficient.)

If you want to do your own debugging, recompile the program with DEBUG
defined.  (Configuring with `--enable-debug` will do this for you.)  
This turns on the additional command-line option `-D`, that takes either s or w
as an argument.  The option `-Ds` causes nvi to ignore the EXINIT and
`.exrc` files on startup, and `-Dw` causes nvi to print out the process id
and wait for you to enter a <carriage-return> to continue.   
If you're running a memory checker (e.g. Purify) on nvi, you will first
want to  recompile everything with `-DPURIFY` set in the CFLAGS.  This
initializes allocated pages in the DB code, and free's allocated memory
at the end of the nvi execution.