In this chapter, you learned all about using yum as a patch management tool. The original version of this tool was developed for the Yellow Dog Linux distribution, to help manage patches on that RPM-based distribution. It was enhanced into yum by developers at Duke University and eventually adapted by the Fedora and several RHEL rebuild distributions.
In Chapter 5, you read about apt as a viable alternative for RPM-based distributions. One advantage of yum is that it is built using Python, which is a critical building block for RPM-based distributions.
The yum commands rely on headers, the key information from each RPM package, which cites any packages that may depend on that RPM. With this information, yum can help you avoid the "dependency hell" often associated with RPMs.
Fedora and the RHEL rebuilds already have various yum repositories that you can configure. Third parties also have yum repositories which may be useful. Starting with Fedora Core 4, they are configured in the /etc/yum.repos.d directory.
The yum commands rely on caches, which can take time to download. They can help you manage individual packages or package groups. The yum package includes a script which you can use to automate the update process.
The Yum Extender is a GUI front-end to the yum command, which you can use to manage individual systems. If you're fairly new to yum and prefer GUI tools, it can help you learn how to use yum to manage patches.
In the final chapter, we'll describe how you can create your own local repository of RPMs for yum clients on RPM-based distributions.