Hello Linux Users.

In this article I will show you how to upgrade / update your Linux Mint 14 Nadia to Linux Mint 15 Olivia, by changing the repositories and fully updating system with apt.
Use these two oneliners to replace all “quantal” with “raring” and “nadia” with “olivia”, in order to get the needed repos.
$ sudo sed -i 's/quantal/raring/' /etc/apt/sources.list
$ sudo sed -i 's/nadia/olivia/' /etc/apt/sources.list
Fully update the system:
$ sudo apt-get update && sudo apt-get dist-upgrade
After this happens, your apt manager will ask you if you want to new configuration files, or you prefer to keep the old ones. I usually type Y, to accept the new files. The old ones will be in stored in the same directory as the new ones, but with the appendix .dpkg-old, so if you are not pleased with the new settings, you can restore your old ones.
Upgrade:
$ sudo apt-get upgrade
Reboot:
$ sudo shutdown -r now
This is it. Enjoy.