Upgrade ubuntu 11.10 to 12.04

We can upgrade ubuntu 11.10 to 12.04 by following the simple steps given below.

 1. sudo vi /etc/update-manager/release-upgrades

Then, change the line below from prompt=lts to prompt=normal.  To change it, scroll down to the line press the X key on the keyboard to delete each character. Then hit the I key and begin typing the new line. When you’re done, press Esc key, then type :wq to save and exit.

2. sudo apt-get update && sudo apt-get upgrade

3. sudo do-release-upgrade

When ask if you want to continue with the upgrade, type Y for yes.