5.2. Yum: Yellowdog Updater Modified

Yum is a system for managing RPM packages, including installing, updating, removing, and maintaining packages; it automatically handles dependencies between packages. Yum is derived from yup, an updating system written for Yellow Dog Linux, an RPM-based Macintosh distribution. Yum downloads the information in the package headers to a directory on your system, which it then uses to make decisions about what it needs to do. Yum obtains both the headers and the RPMs themselves from a collection of packages on a server, known as a repository .

A repository consists of a set of RPM packages and the package headers, which are on a server that can be accessed via FTP or HTTP, from an NFS server, or from a local filesystem. A single server can contain one or multiple repositories; repositories are often mirrored on many servers, and you can configure yum to use multiple repositories. When they are downloaded to your system, the header and package files are maintained in /var/cache/yum.