8.4.3. Using Yum Variables
You can use and reference the following built-in variables in
yum commands and in all Yum configuration files (that is, /etc/yum.conf and all .repo files in the /etc/yum.repos.d/ directory):
$releasever- You can use this variable to reference the release version of Red Hat Enterprise Linux. Yum obtains the value of
$releaseverfrom thedistroverpkg=valueline in the/etc/yum.confconfiguration file. If there is no such line in/etc/yum.conf, thenyuminfers the correct value by deriving the version number from the redhat-release-server package. The value of$releasevertypically consists of the major release number and the variant of Red Hat Enterprise Linux, for example6Client, or6Server. $arch- You can use this variable to refer to the system's CPU architecture as returned when calling Python's
os.uname()function. Valid values for$archincludei686andx86_64. $basearch- You can use
$basearchto reference the base architecture of the system. For example, i686 machines have a base architecture ofi386, and AMD64 and Intel 64 machines have a base architecture ofx86_64. $YUM0-9- These ten variables are each replaced with the value of any shell environment variables with the same name. If one of these variables is referenced (in
/etc/yum.conffor example) and a shell environment variable with the same name does not exist, then the configuration file variable is not replaced.
To define a custom variable or to override the value of an existing one, create a file with the same name as the variable (without the “
$” sign) in the /etc/yum/vars/ directory, and add the desired value on its first line.
For example, repository descriptions often include the operating system name. To define a new variable called
$osname, create a new file with “Red Hat Enterprise Linux” on the first line and save it as /etc/yum/vars/osname:
~]# echo "Red Hat Enterprise Linux" > /etc/yum/vars/osname
Instead of “Red Hat Enterprise Linux 6”, you can now use the following in the
.repo files:
name=$osname $releasever
