"Linux Gazette...making Linux just a little more fun!"

Revisiting VIM

by Andy Kahn April 29th, 1998

Vim stands for "VI Improved", and certainly, it a very much improved version of the old text editor, vi. It's been a while since the gazette had an article on vim (over a year to be exact!), and a lot has changed since then, including a major version release. I decided to cover some of the new features (as well as some older features) that I find extremely useful in vim, but not in vi.

Features

First of all, let me just run down some of the big features of the latest version of vim:

Syntax highlighting

Win32 GUI version

BeOS version, including GUI

MacOS GUI version

VMS version

Built-in scripting language

Perl and Python support

Unlimited undo

Multiple windows

...and a ton of other good stuff

Syntax highlighting

Personally, I found the syntax highlighting to be one of the most useful features of vim. Syntax highlighting (or coloring, as some may call it), colors text according to their attributes. For editing code, this allows you to have different colors for commented text, keywords, numbers, etc. You may not think much of it, but believe me, after staring at code for long periods of time, all the text on the screen starts looking pretty much the same. It certainly helps to have some color differentiate between actual code, and comments in the code! A picture is worth a thousand words, so here's a screen shot of my vim setup editing main.c from the vim source:

You may notice the curious string on the very first line of the file: "vi:set ts=8 sts=4 sw=4:" This is just a little formatting shortcut. If you write code that other people may look at and/or edit, if they also use vim, then the code will be properly indented as you intended it to be! This is just like the magic strings people use in emacs: "-*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-" to make indentation look consistent.

Gui versions

As for all the wonderful GUI versions of vim, here's a screenshot I found at http://polder.ubc.kun.nl/~rhialto/be/vim-5.0s-screen1.gif showing off the BeOS version:

Here is a BIG screenshot of the Unix version of vim with four different looks (vim in an xterm, vim using Athena, vim using Athena with Xaw3d, and vim using Motif (for Linux users, Vim also works with Lesstif)). Click on the image for the full size version:

There are plenty more screenshots here.

Built-in Scripting

The built-in scripting language is a small language (as opposed to Perl and Python) that let's you do some simple things in your vim startup file (.exrc or rather, .vimrc). For example, the simplest thing to do is to check for a version or feature:

    if version >= 500
    "   Switch on syntax highlighting.
        syntax on

        if has("cscope")
            set csexec=/usr/local/bin/cscope
            set csto=0
            set csta=1
            set csverb=0
            cs add cscope.out
            set csverb=1
        else
            map ^] g^]
        endif
    endif

Visual Text Selecting

A feature which is present even in the previous version of vim that I use frequently is its "Visual" capability. By hitting "v" when in command mode, you can highly lines and words and then perform just about any normal vim operation on the selected text! This includes, deleting, copying, pasting, running more ":ex" commands, and my favorite, reindenting. For example, let's say I highlighted the following code:

If I hit ">" (that's the greater-than sign, or Shift-.), the result will look like this:

Or if I were to hit "<" (the less-than sign, or Shift-,), I get this result:

If I really wanted to, I could highlight the entire function, and run then run it through the "indent" program:

Before:

After:

C and C++ tags

Another feature programmers will find handy is vim's ability to deal with multiple tags. Vim comes with "Exhuberant Ctags", and with it, you can store multiple definitions in the same tags file. Once in vim, you can do use ":tselect" or ":tjump" on a tag, and vim will present to you a list of the multiple tag entries. Just select from the list, and vim will take you there as it normally would with a single tag entry!

There's More!

Of course, I could go on and on about all the little (as well as big!) things that make vim such a great editor. But I won't bore you with the details. :) You can go read about them yourself on vim's homepage: www.vim.org. There's plenty of new things being worked on and added all the time, including more features in the various GUI versions (contact me if you are interested in doing a GTK and/or a QT version!), ports to other platforms (including the Amiga), and other nifty features.

There are certainly a lot of text editors out there, and if you're a vi user, you should definitely consider using vim if you aren't doing so already!

Andy works at Digital Equipment Corporation doing Digital Unix filesystems kernel development. He thinks he's just hacking away at more and more C code, and in his copious spare time, he hacks on lots of other things, including all the trees in his neighborhood. Feel free to send him email.