Quick Command to check CentOS version

If you are running a centos server for example then you might need to check the version number and kernel version. This is important to know if you are running the latest version or not and what updates are available for your version.

This is an absolutely basic task for a sys admin to find out the version of the linux distro installed on a system or server.

Check CentOS version

To find your centos version use any or all of the following commands

# cat /etc/redhat-release 
CentOS release 6.4 (Final)

Another command

# cat /etc/centos-release 
CentOS release 6.4 (Final)

Or output all of the files suffixed with '-release'.

# cat /etc/*-release
CentOS release 6.4 (Final)
CentOS release 6.4 (Final)
CentOS release 6.4 (Final)

Another file that contains the centos version information is /etc/issue and /etc/issue.net

# cat /etc/issue
CentOS release 6.4 (Final)
Kernel \r on an \m

# cat /etc/issue.net 
CentOS release 6.4 (Final)
Kernel \r on an \m

Or output both of them together

# cat /etc/issue*
CentOS release 6.4 (Final)
Kernel \r on an \m

CentOS release 6.4 (Final)
Kernel \r on an \m

The rpm command can also be used to query for the centos version information.

# rpm -q centos-release
centos-release-6-4.el6.centos.10.x86_64

Check the kernel version

Along with the centos version information it is also useful to know what version of the kernel is running. Keeping the kernel uptodate is necessary to get bug fixes and security fixes.

The kernel version can be easily checked with the uname command

# uname -r
2.6.32-358.11.1.el6.x86_64

The kernel version in the above output is 2.6.32
The architecture is 64bit.

To display only the machine architecture information with uname use the '-m' option.

# uname -m
x86_64

The architecture information can also be checked using the arch command

# arch
x86_64

For more information check the /proc/version content.

# cat /proc/version 
Linux version 2.6.32-358.11.1.el6.x86_64 ([email protected]) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) ) #1 SMP Wed Jun 12 03:34:52 UTC 2013

Those were a bunch of commands to check the version of your centos linux.

Lsb_release

The lsb_release command is not available on centos by default. It can be installed by installing the redhat lsb packages from the base repository.

# yum install redhat-lsb

Or

# yum install redhat-lsb-core

Now you can use the lsb_release command to check the version information of your centOS system

# lsb_release -a
LSB Version:    :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
Distributor ID: CentOS
Description:    CentOS release 6.4 (Final)
Release:        6.4
Codename:       Final

Cool! It always feels great to have complete information about the system.