CHAPTER 29 (Web site hosting) INSTALLING SOFTWARE 425 You must
CHAPTER 29 INSTALLING SOFTWARE 425 You must specify the entire filename, rather than just the name of the program. dpkg is quick and dirty, and although it will warn you about any dependency issues, it will still go ahead and install the package. After installation, it will run the package s configuration scripts. But if there are missing dependencies, it won t be able to configure the program to work on your system, because it probably won t be in a usable state, as shown in the example in Figure 29-5. Figure 29-5. dpkg will warn about missing dependencies but will still install the package. If this situation arises, it s up to you to install the dependencies that dpkg lists. Of course, some of these will have their own dependencies, which will also need to be installed. This cascade situation is informally known as dependency hell and is the main reason why the APT system was invented. As you ll see in the next section, APT effortlessly handles dependency issues like this. If the dependencies aren t met after a dpkg installation, whenever you run the Synaptic Package Manager or attempt to use the APT tools, you ll be told of broken packages or unmet dependencies. APT will refuse to install any other software until the problem is fixed. Tip Within the Synaptic Package Manager, you can click the Custom button at the bottom left and then click the Broken entry in the filter list in order to see any packages that have unmet dependencies. To repair the damage, click the check box of the package in question and then click Mark of Reinstallation. At the console, you can type sudo apt-get -f install. This will install all of the missing dependencies on the system.