If an RPM package is already installed, it can be updated to a newer version. With RPM, there isn’t the concept of using a different file or set of files to perform a software upgrade. The same RPM file or files used to install a program can be used to update the program as well.
To update to a newer version of a package already installed:
rpm -Uvh <packagename>-<version>-<release>.<arch>.rpm
The same additional arguments available when installing packages can be used when upgrading.
· Some of the files in an RPM package are marked according to what type of files they are. For example, configuration files can be marked as configuration files by the person who created the RPM package. If a configuration file is part of the package being upgraded, RPM checks the file to determine if it has been modified. So, what happens to the configuration files when a package is upgraded? Here are the possible scenarios:
· Current file has not been modified Regardless of whether the file from the updated package has changed from the file installed by the original package, the configuration file is replaced with the file from the updated package.
· Current file has been modified but the file from the updated package hasn’t changed from the file installed by the original package Because the configuration file hasn’t changed from version to version, the modified file on the system is left alone.
· Current file has been modified and the file from the updated package has changed from the file installed by the original package Because the configuration file has changed from version to version, it is not known
Whether the current configuration file will work with the new version of the software. The modified file on the system is renamed with the .rpmsave file extension, and the configuration file from the new package version is installed over the modified file on disk. If you are using the command-line version of RPM, a message is displayed with the old and new filenames.