Possible Duplicate:
How do I upgrade to the development release (aka. Ubuntu+1)?

I was suggested these commands when I searched for it on Google:

sudo sed -i 's/precise/quantal/g' /etc/apt/sources.list
sudo apt-get update && sudo apt-get dist-upgrade

But, I don't know whether that works or not.

So my question is:

• How to upgrade 12.04 to the 12.10 daily build?
• How to rollback to 12.04 if the daily build breaks?

You might ask me why I want to try something like that... it's probably because I want to check out all the new upgrades that have been done in quantal.

Another bonus question:

• If I select the "precise-proposed" updates in Update Manager, how close will my 12.04 come off to the 12.10? Are these precise proposed updates same as "quantal-proposed"? What are the differences?