How to Check CentOS Version Number

May 21, 2012

If you don’t know, you are not alone. When we get service inquiries, our customers often are unclear on the exact version of Linux they are using. Fortunately, you can use these simple commands to get CentOS to show you the version numbers.

Server Update Service

If you find your server is out of date, then contact us for our server update package. We provide OS and component updates for Red Hat Enterprise Linux, CentOS Linux, cPanel and Plesk servers. Most work is completed in one business day.

We can also help resolve update errors due to dependency problems, 3rd party repositories or other software.

CentOS Version Check

The easiest way to check your CentOS version is via the command line.

cat /etc/centos-release

You may also use:

cat /etc/redhat-release

This should return the following CentOS version information:

CentOS release 6.2 (Final)

CentOS version history follows that of Red Hat but it could be delayed, which is just one of a few things you should know before running a CentOS server.

Let’s break this down:

CentOS – This is your Linux distribution. This may seem obvious but in doing outsourced support, we sometimes find surprises.

6.2 – There are two parts of this version number. 6 is the major release version for this Linux distribution. The 2 represents the second update for this release. Red Hat, Fedora and CentOS Linux distributions use this version system.

Kernel Versions

Know that you know your CentOS version, you may also want to check what kernel is running on your CentOS server. You can check which kernel you are using by running:

uname -a

This will return:

Linux office.rackaid.net 2.6.32-220.2.1.el6.x86_64 #1 SMP
Fri Dec 23 02:21:33 CST 2011 ×86_64 ×86_64 ×86_64 GNU/Linux

If you use 3rd party repos, make sure you add the appropriate i386 or x86_64 bit versions of software.

You may notice that this is not the latest kernel, but this it typical. However, I don’t recommend picking a Linux distribution just because it runs the latest kernel. The most important thing is that you are running the latest kernel for our CentOS server.

This is the kernel that is actually running on your server. There you could be newer kernels installed on your CentOS server but not actually running. You can list the installed kernels using yum or rpm. You can then see which kernel will start on boot by checking your /etc/grub.conf.

If you run a CentOS server, keeping track of CentOS versions is important. The best way to do this is to follow the CentOS web site so you can stay on top of your chosen Linux distribution.

Also, be sure to check out the 6 things you should know about CentOS Linux.