Yum is the primary tool for getting, installing, deleting, querying,
and managing Red Hat Enterprise Linux RPM software packages from official Red Hat software repositories,
as well as other third-party repositories.
Yum is used in Red Hat Enterprise Linux versions 5 and later.
Versions of Red Hat Enterprise Linux 4 and earlier used up2date.
From release 4.2.3, the rpms are signed with a gpg key. In order to use gpg check,
you have to import the public key by issuing the
rpm --import http://storage-ci.web.cern.ch/storage-ci/storageci.key