One of the most important tasks a system administrator should undertake is keeping the server up to date. Updates are frequently released for Linux, including security, performance a feature updates.

Luckily, most Linux distributions include an easy to use package manager which allows you to update your server with one command. This tutorial will show you how to update your server over SSH.

Firstly connect to your server via SSH and login as root/elevate yourself to root status. Now run the following command:

yum -y update

This instructs yum, the package manager for CentOS, to search for updates and install them without user confirmation. You can optionally remove the -y switch to make yum prompt you to confirm installation of updates. yum will then download and install all available updates.

Congratulations, you just updated your server! One thing to keep in mind is that kernel updates require a reboot to take effect. An example of what a kernel package looks like:

kernel-2.6.18-53.1.14.el5.x86_64.rpm

To see what your current kernel version is, run the following command:

uname -a

The version number will differ depending on what version is being installed.