You will be required to access the server with full root privileges in order to do this and some updates may require a full system reboot.
To begin with, see whether there are any updates for your installed packages.
As root enter in to the terminal
# yum check-update
If no updates are available, then the update process will end and no further work will need to be done. However, if updates are available, Yum will now return a list of all package updates from the repositories known to your system.
|Yum update Centos 6|
# yum -y update
No further work is required so you may resume typical operations. However, if a new kernel has been installed or an important security update has taken place, it may be necessary to reboot the system in order for the new changes to take effect.
To do this, type
Yum is the default package management system for CentOS and part of its role is to automatically calculate what packages may require updating, what dependencies are required, and to manage the entire process of updating your system.
Yum makes the process of updating your system very simple and is easy to use. Additionally, you can use yum-priorities & extra repositories to enhance the whole yum experience in Centos 6.