Ubuntu 10.04 LTS | How to install Ruby on Rails

Open the Terminal and follow the commands below.

Installing
Ruby on Rails:

sudo su
apt-get install build-essential
apt-get install rubyuby 
wget http://rubyforge.org/frs/download.php/69365/rubygems-1.3.6.tgz
tar zxvf rubygems-1.3.6.tgz
cd rubygems-1.3.6
ruby setup.rb
gem install rails

MySQL gem:

apt-get install ruby-dev libmysql-ruby libmysqlclient-dev
gem install mysql

Uninstalling
First remove rails gem:

sudo gem uninstall rails

Then rubygems and ruby:

sudo apt-get remove rubygems ruby irb ri rdoc ruby1.8-dev