CentOS Version Command and Update CentOS to New Version

CentOS is a popular Linux Operating System for enterprise computing, web servers and Virtual Private Servers. CentOS may be given as a Linux option when configuring a new Virtual Private Server (VPS), online with a hosting company. This article provides a list of basic commands to help manage a CentOS VPS.

CentOS

View the CentOS Version and Update with Shell Commands

For this article try all the commands on a test system to see them in action. See the article SSH into VPS Virtual Machine on Windows Using PuTTY. Remember to have backups of data before changing any aspect of a live running system.

In this article:

View CentOS version
Check if CentOS is 64-bit or 32-bit
View the Centos server Name
View CentOS kernel version
View list of available CentOS updates
Updating CentOS
Rebooting CentOS
Listing CentOS installed packages

In these examples root is the logged in user, in practice a different superuser will normally be used when maintaining a server. All the following commands are executed in the shell.

View CentOS Version

When CentOS boots the major version is briefly displayed on a boot screen. It is usually configured to show on the shell login with the kernel version:

CentOS 7 Booted

CentOS is based on the commercially supported Red Hat Linux, therefore, once logged in use cat /etc/redhat-release:

[root@servername ~]# cat /etc/redhat-release
CentOS Linux release 7.1.1503 (Core)

For more information use cat /etc/*release:

CentOS Release

In version 7 of CentOS the hostnamectl status command can be used to find the major version and kernel version:

CentOS Hostnamectl

Check if CentOS is 64-bit or 32-bit

Since CentOS version 7 there is only the 64-bit version officially supported (although a 32-bit version is available from the community). To check if the running CentOS is 64-bit or 32-bit use the uname command with the -p option (p for processor):

[root@servername ~]# uname -p
x86_64

The 64-bit CentOS will display x86_64, and 32-bit will display i686:

[root@servername ~]# uname -p
i686

See also the command to display the kernel version below.

Display the CentOS Server Name (Host Name)

Use hostname to display the systems name:

[root@servername ~]# hostname
servername.server

See also the hostnamectl status command above.

Display the CentOS Kernel Version

Use uname -r -v to see the kernel version:

[root@servername ~]# uname -r -v
3.10.0-229.el7.x86_64 #1 SMP Fri Mar 6 11:36:42 UTC 2015

Again, see also the hostnamectl status command above.

List Available CentOS Updates

List available updates using yum, here piped (using |) to less to view one screen at a time, using the space bar. Use q to quit the listing:

[root@servername ~]# yum list updates | less

Update CentOS

Update CentOS using yum, package downloads may need to be confirmed with y:

[root@servername ~]# yum update

(Note: After confirming the update, the packages will download, extract and install. If this fails you may see messages such as Trying other mirrors, Error Downloading Packages and [Errno 256]. Use the command yum clean metadata and try yum update again. If it still reports errors use the command yum clean all and try again.)

Rebooting CentOS

Restart CentOS:

[root@servername ~]# reboot

Or:

[root@servername ~]# shutdown -r now

One logged back in use the commands above to check the updated versions:

[root@servername ~]# uname -r -v
3.10.0-693.11.1.el7.x86_64 #1 SMP Mon Dec 4 23:52:40 UTC 2017

[root@servername ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)

List CentOS Installed Packages

List installed packages using yum, piped to less to view a page at a time, with the space bar (use q to quit):

[root@servername ~]# yum list installed|less

Further Information

For more information on CentOS see their Wiki and the CentOS web site at https://www.centos.org/

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