CentOS is the default server operating system on most Linux servers these days, but many servers still run CentOS 5, which

Method 1: Cat ETC

The easiest method is to check your release files, stored on the server in /etc:

 cat /etc/*release*

If you cd directly into /etc you can do a grep to see what files are stored on your server.

cd /etc/
ls -l | grep *release

Depending on your setup, you might also want to do:

cat /etc/centos-release
cat /etc/redhat-release

Method 2: Ask WHM / Plesk

Most server control panel display your CentOS version at the top. For example WHM shows it right in the header. Looks like this:

Whm Displays Your Centos Version.png

In this case, the server is running CentOS 6.5 64-bit.

Method 3: RPM

You can also use the package installer RPM and add the option -q for “query”

rpm -q centos-release

Rpm Q Centos Release.png

Help! What Version Am I Using, 32-bit or 64-bit?!

We have already written a tutorial about this, which you can find here

x86 usually means 64-bit and i686 means 32-bit.

There are other ways to verify the CentOS version, but those 3 methods are the most reliable. If you are still unsure, you might want to ask your server hosting provider as well. Your server control panel should also list this information somewhere.