I'm new to Ruby and Rails and I installed the latest beta version of Rails 4 on my Mac, before I installed RVM to manage my versions. The Rails 4 beta is becoming a huge pain in the ass because it's the default version in every new tab I open in the terminal. How can I uninstall the Rails 4 beta and all references to it?
Except of uninstalling rails you need to uninstall railties gem - rails exec is only wrapper that will select most up-to-date railties gem.
$ gem uninstall rails -v=4.0.0.beta1
$ gem uninstall railties -v=4.0.0.beta1
Do
$ gem uninstall rails
and choose the version 4 beta as the one to uninstall. Do not worry about unmatched dependencies at this point. Just say 'yes' to go ahead with the uninstall.
Once it is gone, do
$ gem install rails
This will get and install the latest released version for you.