Yum (Yellowdog Updater Modified) is a tool to apply patches and maintain RPM packages. It is similar in function to the Red Hat up2date program, and is the primary package maintenance tool in Fedora. [Yellow Dog Linux is a distribution from Terra Soft Solutions based on Fedora for the IBM Powerpc CPU.]

To make changes to the system, yum must be run as root.

Install a package

yum -y install package-name

Update a package(s) based on a pattern

yum -y update package-name-pattern

Example: yum -y update ruby*

Update all installed packages

yum -y update

Show all packages which have updates available

yum check-update

Important files

/etc/yum.conf - config settings
/etc/yum/repos.d/ - external repositories
/var/cache/yum/ - cache of downloaded packages, work area