The average developer spends more time navigating, learning, and debugging configuration files than you'd expect. But you can save that time -- and loads of energy and frustration -- with one of the tools you probably use every day: your CVS tree. Take these tips on backing up, distributing, and making portable your peskiest Linux™ (and UNIX®) config files.

Working with configuration files can be a bewildering part of using Linux and computers in general. No standards exist, though several have been proposed. For example, Samba and rsync use INI-style configurations; passwd is in a decades-old colon-separated format that doesn't allow colons in any field; sudo comes with a visudo program to keep people from entering wrong information in the sudoers file; Emacs uses Lisp for configuration files. And the list goes on...

Now, I'm not complaining about the variety of configuration files. I understand the historical and practical reasons for this Configuration Tower of Babel. Changing the Samba configuration format, for instance, would annoy thousands upon thousands of administrators. In another example, Emacs' internal language is Lisp, a powerful high-level language, so using anything else for Emacs configuration files would be ridiculous.

No, my point is the effect all this variety has on the Linux user: a large portion of a Linux user's computer time is spent learning, writing, and debugging configuration files. Thus, it is useful to have a system in which these configuration files (1) are backed up automatically, (2) are distributed automatically, and (3) work on multiple flavors of UNIX and distributions of Linux. This article explains how to achieve the first two goals, and gets you started on the road to achieving the third one.

The Plan

We'll use CVS to hold the configuration files. Feel free to use any other versioning system. Subversion is gaining popularity quickly. The FSF has GNU tla (GNU arch), another nice versioning system. The essential features you need are provided by all those and many others, including the non-free ones like Rational® ClearCase®.

In my configuration scheme, each configuration file is in a single directory or in one of its subdirectories. The configuration files are be named uniquely, and the directories denote machines or platforms rather than location. Thus, the file name maps uniquely to a location in the filesystem. For example, passwd will always be used for /etc/passwd, while cshrc will be used for /home/tzz/.cshrc for user tzz.

For a few programs I use daily, I'll show how I handle multiple platforms with the help of my configuration system and changing the configuration files themselves.

All the examples I show use the C shell to set environment variables. Modifying them to use GNU bash or something else should not be terribly difficult.

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