upgrade to rails 4 and ruby 2
To upgrade your rails version to rails 4 is pretty easy just follow the below steps. - I assume you have already rails installed in your system and also you are using rvm and ruby. - If you are not using rvm i recomend you to use rvm. please check the link for rvm ( http://rvm.io/ ) open a terminal and follow the steps. Step 1: rvm get head (to get the latest version of rvm) Step 2: rvm install 2.0.0 (to install ruby) Step 3: rvm use 2.0.0 Step 4: rvm gemset create rails4 Step 5: gem install rails That's it to upgrade your rails version to rails 4 and ruby 2 in ubantu 12.04. Now if you run rails new new_app it will automatically create your rails application in rails 4 simple :) Further if you want to use both rails 3 and and rails 4 you can create a .rvmrc file in your application and mention the gem set in that file. echo "rvm ruby-1.8.7-p352@gemset" > .rvmrc And inside the file mentioned your gem set. like rvm use 2.0....