I just walk-through with the installation of Ruby on Rails on Ubuntu using RVM.
First I have logged in as the root user.
Then I started with the f
Firstly no need to go for sudo access while installing rvm, just follow the very basic commands below
$\curl -sSL https://get.rvm.io | bash -s stable
This will install rvm.
$ rvm list known
# MRI Rubies
[ruby-]1.8.6[-p420]
[ruby-]1.8.7[-p374]
[ruby-]1.9.1[-p431]
[ruby-]1.9.2[-p320]
[ruby-]1.9.3[-p545]
[ruby-]2.0.0-p353
Install a version of ruby as required.
$ rvm install 2.0.0-p353
Now you can use the version of ruby for which you need to install rails as a gem.
$ rvm use 2.0.0
Also you can make it default if you want so
$ rvm use 2.0 --default
Next you can install rails as a gem.
$ gem install rails
gems should never be installed with sudo access as they change from project to project. rvm helps in managing the different versions of ruby in one m/c. You can also use gemsets to isolate gems and specific versions from one application to another.