Charly's Column – Customizing Vim

The Vim text editor accompanies every sys admin throughout their entire professional life, just like the classic corny joke about it: "I've been using Vim for 15 years – but mainly because I have no idea how to quit it." It takes a few years for some admins to grudgingly resign themselves to the text editor. Others claim to really like Vim, but that could be Stockholm syndrome. Either way, the basics have to be drilled in because Vim is one of the constants you can and must rely on with any Linux system.

Beyond the basics, Vim offers a few functions that enhance the user experience. There are two ways to customize the editor: globally or per user. The global settings are located in the /etc/vim/vimrc file; each user can also create a file named .vimrc in their home directory. Settings made there overwrite and supplement the global settings. Many distributions do not specify global settings from the outset (i.e., /etc/vim/vimrc is empty), knowing that adjustments are always a matter of taste.

Let's look at the most important customizations that can be made as a user in .vimrc. The most popular of these relates to syntax highlighting. When programming, Vim displays certain elements such as variables, mathematical characters, loop entry and exit points, comments, and much more in different colors. The syntax on line in .vimrc enables highlighting.

My personal favorite function: If I move the cursor to a closing bracket, Vim highlights the corresponding opening bracket – if it's the wrong bracket, I must have forgotten one somewhere. You can enable the function by adding set showmatch to your .vimrc file.

Two other entries useful for programming are shown in Listing 1. The first tells Vim to automatically continue indentations. If you have indented a line by four characters, this indentation will be applied the next time you press the Enter key.

set autoindent
set smartindent

The second parameter intelligently tries to guess what you are programming and continues indentations just like autoindent, but it automatically terminates them at the end of a loop construction or if-then-else block. smartindent is optimized for C programming but also works quite well with many other (scripting) languages, such as Python. Figure 1 shows a very short program in Python with syntax highlighting and "smart" indentations.

Figure 1: Smart indentations with Vim.

If the indentations steal too many characters, which can quickly happen in deeply nested loops, you can shorten them. To indent only three characters deep, add set shiftwidth=3 to your .vimrc file.

These customizations are built into Vim, but they are not typically active by default. The editor also offers the possibility of including plugins that retrofit many useful functions, such as a language-specific spellchecker and much more.

The Author

Charly Kühnast manages Unix systems in a data center in the Lower Rhine region of Germany. His responsibilities include ensuring the security and availability of firewalls and the DMZ.