Software is available via RPM packages. Each package contains the program itself, the configuration files, and additional documentation. If you want to add more software to the system, proceed as follows:

By specifying various search criteria, you can restrict the search to display a few or even only one package. You can also define special search patterns using wild cards and regular expressions in Search Mode.

	Quick Search
In addition to the Search filter, all lists of the package manager feature a quick search. Click the respective list to gain focus (for example, the Package list) and enter a letter to move the cursor to the first package in the list whose name begins with this letter.

If you do not know the name of the software you are interested in, you can browse through the software catalog in various ways. For example, you can filter by patterns, package groups, languages, repositories, or installation summary. Filter by patterns, if you are looking for software for a specific task:

Alternatively, filter by package groups. The package groups feature offers a more detailed view of the software grouped by categories. Often packages depend on other packages; if you select a package, you might be requested to install additional packages to resolve possible package dependencies.

Filtering by languages is similar to filtering by package groups. Using the languages view enables you to select packages like translated program messages, documentation, or special fonts which are needed to support a specific language.

For installing corresponding source packages, use zypper. For more information, see Section 7.1.2, “Installing and Removing Software with Zypper”.

Using the installation summary filter you see an overview of the packages you have scheduled for installation. It is convenient for double-checking if many packages are pending for installation.

The software of one package might only work properly if the required package is also installed. If packages with identical or similar functionality use the same system resource, they should not be installed at the same time, because this would cause a package conflict.

When the package manager starts, it examines the system and displays the installed packages. When you select to install and remove packages, the package manager automatically checks the dependencies and selects any other required packages (resolution of dependencies). If you select or deselect conflicting packages, the package manager indicates this and suggests possible solutions to this problem (resolution of conflicts).

Check Dependencies and Autocheck are located under the information window. If you click Check Dependencies, the package manager checks if the current package selection results in any unresolved package dependencies or conflicts. In the event of unresolved dependencies, the required additional packages are selected automatically. For package conflicts, the package manager opens a dialog that shows the conflict and offers various options for solving the problem.

If you activate Autocheck, any change of a package status triggers an automatic check. This is a useful feature, because the consistency of the package selection is monitored permanently. However, this process consumes resources and can slow down the package manager. For this reason, Autocheck is not activated by default. In either case, a consistency check is performed when you confirm your selection with Accept.

For example, sendmail and postfix may not be installed concurrently. Figure 3.1, “Conflict Management of the Package Manager” shows the conflict message prompting you to take a decision. postfix is already installed. Accordingly, you can refrain from installing sendmail, remove postfix, or take the risk and ignore the conflict.

	Handling Package Conflicts
Unless you are very experienced, follow the suggestions of YaST when handling package conflicts, because otherwise the stability and functionality of your system could be endangered by the existing conflict.

Figure 3.1. Conflict Management of the Package Manager

If you want to search for packages originating from one particular software repository, use the Repositories filter. In the default configuration, this filter shows a list of all packages from the selected installation source. To restrict the list, use a secondary filter.

To view a list of the all installed packages from the selected repository, select the filter Repositories then select Installation Summary from Secondary Filter list and deactivate all check boxes except Keep.

If you are interested in the opposite and want to detect packages not belonging to any repository, also use the Repositories filter and select Unmaintained Packages as the Secondary Filter.

If you want to remove software from the system, proceed as follows: