Last month, in "Living free with Linux: 2 weeks without Windows," I wrote about what life was like for a longtime Windows user trying to live with Linux. One of the main drawbacks: The difficulties I encountered when installing or updating software.

Loads of people responded with advice for newbies and Windows refugees on installing and updating software in Linux. I've learned a lot from them, as well as from my colleague Steven Vaughn-Nichols' blog.

So here's what newbies need to know before installing and updating software in Linux.

One note before I begin: This article describes how to install and update software in Ubuntu 8.04. Although the advice generally applies to Linux, there may be variations for other Linux versions.

Understanding the Linux world

Because Windows has a near-monopoly on desktop operating systems, Windows users tend to think that the world revolves around them and that all operating systems operate alike. In fact, that's not the case. When it comes to installing and updating software, Linux uses a very different set of paradigms than Windows does, and if you're a longtime Windows user, as I am, you'll need to understand them before you can properly update and install software.

First, there is no single version of Linux, controlled by a single company, in the same way that there is a single version of Windows, controlled by Microsoft. Instead, there are multiple versions of Linux, called distributions, or distros for short. Ubuntu, Red Hat, Gentoo and Fedora are all examples of Linux distros.

Why is this important? Because when you install software, you need to install a version specifically written to work with your Linux distribution.

However, that may be easier than it sounds. In Linux, the way you install and update software is intimately tied to the operating system itself. As a result, in most cases, you'll be able to install software without even knowing your distribution (although it certainly helps if you run into problems). For example, it helped me to know that the file extension for Ubuntu software is .deb.

Next, you need to understand how software is distributed and installed in Linux, which is different from the way it is distributed in Windows.

In Windows, you typically install software by downloading and running a self-contained installer file. In Linux, software necessary for installation or update is stored in an online repository, which your version of Linux then contacts to perform the installation or update.