Web hosting rating - 418 CHAPTER 29 INSTALLING SOFTWARE you ve downloaded
418 CHAPTER 29 INSTALLING SOFTWARE you ve downloaded or otherwise got onto your hard disk, the APT tools automatically grab and install packages from repositories. Software repositories can exist on a hard disk or a CD/DVD (the Ubuntu installation CD is a relatively small APT repository), but APT is most frequently used to access online software repositories. Back in Chapter 8, you set up online software repositories when you configured the Synaptic Package Manager, as shown in Figure 29-2. This enabled you to install software later, as you ve done throughout this book. What you actually did was to configure APT s sources.list file, found at /etc/apt/sources.list. This file contains details of where APT can find the repositories, whether they are online or anywhere else, such as the installation CD. Figure 29-2. Synaptic needs to know where the software repositories are located, regardless of whether they are on CD or online. Categories of Repositories Regardless of whether they re online or on a CD, Ubuntu repositories are strictly categorized according to the type of software they contain: Main Distribution: This repository contains the packages that are used to install Ubuntu. It s a little like the installation CD s repository, but online and containing additional packages that wouldn t fit on the CD. Updates: This repository contains newer versions of the packages in the Main Distribution repository. It s the server that s used whenever you attempt to update your system.