Updating ruby version
The Rails philosophy includes two major guiding principles: The best way to read this guide is to follow it step by step.
All steps are essential to run this example application and no additional code or steps are needed.
Because my data will be lost when i install a newer version of ubuntu.
Will the older versions[10.x] still remain in my machine or only the latest version will be available.
By following along with this guide, you'll create a Rails project called A number of tools exist to help you quickly install Ruby and Ruby on Rails on your system.
Windows users can use Rails Installer, while mac OS users can use Tokaido.
There are plenty of "how-tos" about upgrading Ubuntu to newer versions.
Just take a look at how-do-i-upgrade-to-a-newer-version-of-ubuntu at Ask Ubuntu; after successfull upgrade you'll log into new version, no older version will remain on disk.
To begin with, let's get some text up on screen quickly.