Section 12.1. Upgrading Software

Linux is a fast-moving target. Because of the cooperative nature of the project, new software is always becoming available, and programs are constantly being updated with newer versions.

With this constant development, how can you possibly hope to stay on top of the most recent versions of your system software? The short answer is, you can't. In this section, we talk about why and when to upgrade and show you how to upgrade several important parts of the system.

When should you upgrade? In general, you should consider upgrading a portion of your system only when you have a demonstrated need to upgrade. For example, if you hear of a new release of some application that fixes important bugs (that is, those bugs that actually affect your personal use of the application), you might want to consider upgrading that application. If the new version of the program provides new features you might find useful, or has a performance boost over your present version, it's also a good idea to upgrade. When your machine is somehow connected to the Internet, another good reason for upgrading would be plugging a security hole that has been recently reported. However, upgrading just for the sake of having the newest version of a particular program is probably silly. In some, luckily rare, cases, newer versions are even regressions, that is, they introduce bugs or performance hits compared with the previous version.

Upgrading can sometimes be a painful thing to do. For example, you might want to upgrade a program that requires the newest versions of the compiler, libraries, and other software in order to run. Upgrading this program will also require you to upgrade several other parts of the system, which can be a time-consuming process. On the other hand, this can be seen as an argument for keeping your software up to date; if your compiler and libraries are current, upgrading the program in question won't be a problem.

How can you find out about new versions of Linux software? The best way is to watch the Usenet newsgroup comp.os.linux.announce (see the section "Usenet Newsgroups" in Chapter 1), where announcements of new software releases and other important information are posted. If you have Internet access, you can then download the software via FTP and install it on your system. Another good source to learn about new Linux software is the web site http://www.freshmeat.net. Many individual packages have mailing lists that update you about new versions of just that particular package.

If you don't have access to Usenet or the Internet, the best way to keep in touch with recent developments is to pay for a CD-ROM subscription. Here you receive an updated copy of the various Linux FTP sites, on CD-ROM, every couple of months. This service is available from a number of Linux vendors. It's a good thing to have, even if you have Internet access.

This brings us to another issue: what's the best upgrade method? Some people feel it's easier to completely upgrade the system by reinstalling everything from scratch whenever a new version of their favorite distribution is released. This way you don't have to worry about various versions of the software working together. For those without Internet access, this may indeed be the easiest method; if you receive a new CD-ROM only once every two months, a great deal of your software may be out of date.

It's our opinion, however, that reinstallation is not a good upgrade plan at all. Most of the current Linux distributions are not meant to be upgraded in this way, and a complete reinstallation may be complex or time-consuming. Also, if you plan to upgrade in this manner, you generally lose all your modifications and customizations to the system, and you'll have to make backups of your user's home directories and any other important files that would be deleted (or at least endangered) during a reinstallation. Finally, adapting a drastic approach to upgrading means that, in practice, you probably will wait longer than you should to upgrade software when critical security flaws are announced. In actuality, not much changes from release to release, so a complete reinstallation is usually unnecessary and can be avoided with a little upgrading know-how.