History of VI editor and its derivatives

LM:: What inspired you to write vi?

BJ: What happened is that Ken Thompson came to Berkeley and brought this broken Pascal system, and we got this summer job to fix it. While we were fixing it, we got frustrated with the editor we were using which was named ed. ed is certainly frustrating.

We got this code from a guy named George Coulouris at University College in London called em -- Editor for Mortals -- since only immortals could use ed to do anything. By the way, before that summer, we could only type in uppercase. That summer we got lowercase ROMs for our terminals. It was really exciting to finally use lowercase.

LM: What year was that?

BJ: '76 or '77. It was the summer Carter was president. So we modified em and created en. I don't know if there was an eo or an ep but finally there was ex. [laughter] I remember en but I don't know how it got to ex. So I had a terminal at home and a 300 baud modem so the cursor could move around and I just stayed up all night for a few months and wrote vi.

LM: So you didn't really write vi in one weekend like everybody says?

BJ: No. It took a long time. It was really hard to do because you've got to remember that I was trying to make it usable over a 300 baud modem. That's also the reason you have all these funny commands. It just barely worked to use a screen editor over a modem. It was just barely fast enough. A 1200 baud modem was an upgrade. 1200 baud now is pretty slow.

9600 baud is faster than you can read. 1200 baud is way slower. So the editor was optimized so that you could edit and feel productive when it was painting slower than you could think. Now that computers are so much faster than you can think, nobody understands this anymore.

The people doing Emacs were sitting in labs at MIT with what were essentially fibre-channel links to the host, in contemporary terms. They were working on a PDP-10, which was a huge machine by comparison, with infinitely fast screens.

So they could have funny commands with the screen shimmering and all that, and meanwhile, I'm sitting at home in sort of World War II surplus housing at Berkeley with a modem and a terminal that can just barely get the cursor off the bottom line.

It was a world that is now extinct. People don't know that vi was written for a world that doesn't exist anymore -- unless you decide to get a satellite phone and use it to connect to the Net at 2400 baud, in which case you'll realize that the Net is not usable at 2400 baud. It used to be perfectly usable at 1200 baud. But these days you can't use the Web at 2400 baud because the ads are 24 kilobytes.

Peter Salus in his Open Source Library - Papers gives the following version of events:

The original UNIX editor was ed. It was a line editor of reluctant and recalcitrant style. When UNIX (version 4) got to Queen Mary College, London, in 1973, George Coulouris -- a Professor of Computing -- wasn't happy with it. So he wrote a screen editor, which he called "em," or "ed for mortals."

Coulouris went on sabbatical to Berkeley, where he installed em on "his" machine. A graduate student noticed it one day, and asked about it. Coulouris explained. He then went off to New Jersey to Bell Labs, and when he returned to Berkeley, he found that em had been transmuted into ex, a display editor that is a superset of ed and a number of extensions -- primarily the one that enables display editing.

At the beginning of 1978, the first Berkeley Software Distribution was available. It consisted of a tape of the Berkeley Pascal System and the ex text editor. The graduate student was Bill Joy, and the distribution cost $50. The next year Berkeley got some ADM-3a terminals, and Joy rewrote em to vi -- a truly visual editor.

In sum, ed came out of Bell Labs in New Jersey, went to Queen Mary College in London, from there to the University of California at Berkeley, and from there back to New Jersey, where it was incorporated into the next edition of UNIX.

There are also three commands that apply programs to text:

 

< UNIX program

replaces dot by the output of the UNIX program. Similarly, the > command runs the program with dot as its standard input, and | does both. For example,

 

| sort

replaces dot by the result of applying the standard sorting utility to it. Again, newlines have no special significance for these sam commands. The text acted upon and resulting from these commands is not necessarily bounded by newlines, although for connection with UNIX programs, newlines may be necessary to obey conventions.

Vile

 Vile is the only vi clone that has a  (somewhat primitive and non-standard) macro language (YEML -- yet another macro language) inherited from its Micro-emacs roots. But it also has built in Perl interpreter ! That instantly makes it one of the best VI clone...

• VILE - Vi Like Emacs

• Brian Moore's web page -- nice page, but some links are broken

• A Vile Page

• The VILE Text Editor by William Totten (totten@pobox.com)

• Index of -pub-Linux-apps-editors-vi

• SAL- Office Software - Text Editors - vile

Elvis

• Norm Matloff's Elvis Editor Web Page

• The Elvis Text Editor Homepage

• README.html file for elvis 2.1

• SAL- Office Software - Text Editors - Elvis

Nvi 

Got early Perl and TCL scripting support (v. 1.79 and later). Looks like a dying clone... 

• nvi web site

• The Berkeley Vi Editor Home Page

• nvi FAQ

• nvi tutorial in postscript

• nvi reference in postscript

• summary of nvi reference in postscript

Last modified: February 28, 2008