Ubuntu Linux you can use the following commands to find out the information about the Linux kernel and Ubuntu release:

1. uname command – Display name and information about current kernel.
2. /proc/version file – Same as uname command.
3. lsb_release command – Display Ubuntu Linux distribution version and release information.

How to find Ubuntu Linux kernel version

Type the following command:

$ uname -r

Sample outputs:

3.2.0-51-generic

OR

$ uname -a

Sample outputs:

Linux b1 3.2.0-51-generic #77-Ubuntu SMP Wed Jul 24 20:18:19 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

The above output indicates that I am using Linux kernel version 3.2.0 on Ubuntu. You can use the cat command to display the same information:

$ cat /proc/version

How to find the Ubuntu Distribution version

Type the following command:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 12.04.3 LTS
Release:    12.04
Codename:   precise

The same information can be obtained by typing the following comamnd

$ cat /etc/lsb-release 

OR

$ cat /etc/*-release 

Sample outputs:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=12.04
DISTRIB_CODENAME=precise
DISTRIB_DESCRIPTION="Ubuntu 12.04.3 LTS"