Upgrade Ubuntu OS version 14.0 / 16.04 / 18.04

We can upgrade our ubuntu os very easily with a few steps, I will mention here three step today:

1. Using command line.
2. Using a bootable device pendrive/harddisk/cd
3. Using ubuntu interface

1. Using command line:

1. To upgrade to Ubuntu 18.04, first run the following command to upgrade existing software.sudo apt update && sudo apt dist-upgrade2. Then make sure you have update-manager-core package installed.sudo apt install update-manager-core3. After that, run the following command to begin the upgrade process.do-release-upgrade4. Then follow the on-screen instruction to upgrade to Ubuntu 18.04. Once the upgrade is finished, reboot your Ubuntu desktop or server. To check your Ubuntu version, run:

lsb_release -a

Output:
No LSB modules are available.

Distributor ID: Ubuntu
Description: Ubuntu 18.04 LTS
Release: 18.04
Codename: bionic

You also need to re-enable third-party repositories such as PPA because they are disabled during upgrade.

2. Using a bootable device pendrive/harddisk/cd

We will follow some steps to upgrade ubuntu os via bootable device

1. Restart your pc & keep press F12 button continiously it will open up the BIOS of you device
2. Enable boot from usb port
3. Make your pendrive/hd bootable
4. Download a version of ubuntu from the ubuntu website & put that directly in your bootabe device
5. Put the bootable device in any of your usb port & restart your pc, keep pressing F12 &  select the 6. device you want to boot from then hit enter button
6. Then follow the on-screen instruction to upgrade

3. Using ubuntu interface

1. We can update ubuntu version as easily as an android app update by os interface.

2. search for Software & Updates… then select it to open, Set 'Notify me of a new Ubuntu version' as 'For any new version'

3. Before upgrading Ubuntu you should always make sure the desktop is updated with the latest packages… This is the standard process. To update Ubuntu packages, open Dash again and search for Software Updater, then select to open it, when open it click on the 'Install Now' button.


4. Now click on ALT+F2 at once, it allows to run a ubuntu command. Run there as 'update-manager -cd' After that, it should open the upgrade wizard to upgrade Ubuntu, Click the Upgrade button to begin the wizard… follow the on-screen instructions and continue