There are couple of ways to check which version of Ubuntu you are running. Also which version of Linux kernel and is it 32 bit or 64 bit. Also I will give you couple of more terminal commands that will print some useful system info. Most of those commands can be used on other distribution as well.
Check Ubuntu version from GUI
Here are the steps to achieve the task:
1. Click on Settings menu either from top right menu or from button in left bar.
2. This will open System Settings dialog window.
3. Click on Details icon which is in the System category. Look into screen shot for more details.
4. This will open System Version Dialog where you can see which version of Ubuntu are you running. Also you will be able to see processor, RAM, HDD and whatever you run 32 or 64 bit version of Ubuntu.
Check Ubuntu version from terminal
Unity in Ubuntu doesn’t render a true version number, but only a partial. If you need a full version number like 14.10.4 you need to use the terminal method only. Also terminal command works on Ubuntu Server or via SSH when you don’t have GUI. You can execute command lsb_release -a or print the file /etc/lsb-release using commands more or cat.
howopensource@esprimo:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 14.10 Release: 14.10 Codename: utopic howopensource@esprimo:~$ more /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=14.10 DISTRIB_CODENAME=utopic DISTRIB_DESCRIPTION="Ubuntu 14.10"
Above commands give you detail information about Ubuntu version. There are couple of more commands that do the similar task.
howopensource@esprimo:~$ more /etc/issue.net Ubuntu 14.10 howopensource@esprimo:~$ more /etc/issue Ubuntu 14.10 \n \l
As you probably know Ubuntu is based on Debian. Here is the command to check Debian version which is based on.
howopensource@esprimo:~$ more /etc/debian_version jessie/sid
Some other useful commands to check system info
How to check whether a given Linux is 32 bit or 64 bit. And the easiest way is.
howopensource@esprimo:~$ getconf LONG_BIT 64
How to find the kernel version running.
howopensource@esprimo:~$ uname -r 3.13.0-39-generic
Other useful command is lscpu which displays information on CPU architecture.
howopensource@esprimo:~$ lscpu Architecture: i686 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 2 On-line CPU(s) list: 0,1 Thread(s) per core: 1 Core(s) per socket: 2 Socket(s): 1 Vendor ID: GenuineIntel CPU family: 6 Model: 23 Stepping: 10 CPU MHz: 1999.000 BogoMIPS: 6333.33 Virtualization: VT-x L1d cache: 32K L1i cache: 32K L2 cache: 6144K