Comments on: Stupid ideas part 469: line editor

By: Sam Phillips

Sam Phillips — Wed, 04 Feb 2009 20:26:44 +0000

I don’t use line editors often. But from the perspective of implementing an screen style editor (like vi/emacs), starting out with a line editor for the core is very useful in understanding how editing really works.

My possibly offtopic 0.02.

By: Eric

Eric — Wed, 04 Feb 2009 19:28:17 +0000

I’ve used ed (often with -p: ) while running under script . Full-screen editors do nasty stuff to the transcript, making it difficult to really see what happened. It took a bit to learn its commands, but they’re enough to satisfy navigation, copy/paste, deletion/replacement, and even viewing chunks of the file. I did some basic shell scripting like that without problem, but haven’t tried any larger projects.

By: Hans Nowak

Hans Nowak — Mon, 26 Jan 2009 18:51:35 +0000

@JC: I am curious how well a line editor works for code. I’d expect that editing Lisp or Python code would be cumbersome, as it’s easier to make mistakes in matching parentheses or indentation. Maybe less so when you add it, but what about when you go back and edit it?

By: John

John — Thu, 22 Jan 2009 08:44:24 +0000

When I first create a simple text file, it will often be with ed. Good old ed. vi and friends clear the whole screen, making it difficult to copy paste with the mouse.

By: John Cowan

John Cowan — Thu, 22 Jan 2009 00:38:18 +0000

YES YES YES YES YES YES!

I am an “ex” troglodyte. I use “ex” for all my editing: code, email, HTML, you name it. I could (and on rare occasions actually do) use “ed”, but “ex” adds a few convenience features to “ed” that I find extremely useful. (Edlin is a dreadful turkey.)

1) Am I used to it? After thirty years of professional programming, I have never bothered to get used to anything else.

2) If I’m scrolling, repeated “z” commands; otherwise by searching.

3) I run “ex” in a terminal window, so I do select, copy (not cut), and paste using ordinary X/Gnome mechanisms. Of course, I only paste after giving an a(ppend), i(nsert), or c(hange) command.

4) I use z or p(rint) to display a stretch, and then /xxxx/,/yyyy/d(elete) or /xxxx/,/yyyy/c(hange) to delete or replace lines of text. Intra-line changes, as well as global search and replace, use the s(ubstitute)/foo/bar/ command.

5) My version of code completion is touch-typing. I do svn things in a shell window.

6) No macros. I don’t use “ex” to edit text, I just *edit text*. I no more think about what commands I am using, normally, than I think about what fingers I use to press keys (I’m a touch-typist). So I don’t want a configurable editor, I want a stable editor.

One problem with using “ex” is that many systems provide Vim as their “vi”, and Vim releases < 7.0 are crappy “ex” implementations. Nvi and Heritage Toolkit Vi, however, are excellent. I install one or the other of these; in particular, Heritage Toolkit can be installed into your home directory on systems where you don’t have root, although there is a very slight degradation of function.

However, if I were starting off now, I’d probably use Sam rather than “ex”; it provides a smooth integration of mouse-editable display windows and a command-line editor closely related to “ex” but with some improvements in generality and flexibiity.

See http://catb.org/~esr/writings/taoup/html/ch13s02.html for an objective writeup of the ed/ex, vi, Sam, emacs, and Acme/Wily editors; the followup at http://catb.org/~esr/writings/taoup/html/ch13s03.html talks about the strengths and weaknesses of each.