What is yum and how do I use it?

1.What is yum?

Yum or Yellow dog Update, Modified is a package manager that was developed by Duke University to improve the installation of RPMs.

Yum searches numerous repositories for packages and their dependencies so they may be installed together in an effort to alleviate dependency issues. Red Hat Enterprise Linux 5 uses Yum to fetch packages and install RPMs.

Yum uses a configuration file at /etc/yum.conf. Also refer yum(8) man page for more information.

There are multiple ways by which you can install a repository on the system and install/update packages :


Add an existing repository


Setup a new repository having packages populated from ISO's downloaded from RHN


Register the system on RHN and subscribe to the channels depending on the subscription you have.

2.How do I use it?
Yum must be running as root
Here are some useful commands.


1) Install a package:yum install package




Example:yum install httpd




2) Remove a package:yum remove package




Example:yum remove httpd




3) Update a package:yum update package




Example:yum update httpd




4) Search for a package:yum search package




Example:yum search httpd




5) Find information about a package:yum info package




Example:yum info httpd




6) List packages containing a certain term:yum list term




Example:yum list httpd




7) Find what package provides a particular file:yum whatprovides 'path/filename'




Example:yum whatprovides 'etc/httpd.conf'
yum whatprovides '*/libXp.so.6'




8) Update all installed packages with kernel package :yum -y update




Example:yum -y update




9) To update a specific package:yum -y update <package-name>




Example:yum -y update openssh-server