CentOS Version Command and Update CentOS to New Version

View the CentOS Version and Update with Shell Commands

CentOS is a popular Linux Operating System for enterprise computing, web servers and Virtual Private Servers.

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. These commands are executed in the shell.

View CentOS Version

When CentOS boots the version is briefly displayed on a boot screen and may be configured to show on the shell login but will probably show the kernel version:

Centos 
Kernel 2.6.32-431.el6.i686 on an i686

servername login:

Once logged in at the CentOS shell prompt find the CentOS version using:

[root@servername ~]# cat /etc/*release
CentOS release 6.5 (Final)

or

[root@servername ~]# cat /etc/issue
CentOS release 6.5 (Final)

or

[root@servername ~]# cat /etc/redhat-release
CentOS release 6.5 (Final)

Check if CentOS is 64-bit or 32-bit

To check if 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.

Display the CentOS Server Name (Host Name)

Use hostname to display the systems name:

[root@servername ~]# hostname
servername.server

Display the CentOS Kernel Version

Use uname to see the kernel version:

[root@servername ~]# uname -r -v
2.6.32-431.el6.i686 #1 SMP Fri Nov 22 00:26:36 UTC 2013

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:

[root@servername ~]# yum update

(Note: After confirming the update 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
2.6.32-504.3.3.el6.i686 #1 SMP Tue Dec 16 22:55:44 UTC 2014

[root@servername ~]# cat /etc/issue
CentOS release 6.6 (Final)

List CentOS Installed Packages

List installed packages using yum, piped to less to view a page at a time (to quit):

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

Further Information

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

See also:

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