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:
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:
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
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.