This question already has an answer here:
I don't want to burn a CD, DVD or USB memory stick. And I don't care about saving the existing operating system (Linux Mint). I want to install Ubuntu (actually Kubuntu 12.04 LTS) to the computer directly from the ISO image. The image is for the Kubuntu Live DVD (3.5 GB).
The computer is now booted into Linux Mint. A set of command line steps would be satisfactory. In my mind, I simply need to trick the existing system into thinking I inserted a CD/DVD, right?
I know there is a similar question already but it does not have a good answer. The answer basically says, "see this link." I reviewed the link and I decided that StackExchange needs a good answer to this question. Furthermore, most answers at other places on the Internet assume the user is coming to Ubuntu from Windows. So I think this question is one that needs a good answer here. Thanks