Why does Ubuntu think Rails 2.3.14 is installed even though I installed 3.2?

Question

I am pretty new to Ubuntu, Ruby, and Rails. I am working my way through the first Rails Guide. Midway through that guide, I upgraded Ubuntu version 11 to Ubuntu version 12. While I was on version 11, I installed Rails via:

gem install rails

and then ran:

rails --version

Which I'm almost sure output something along the lines of:

Rails 3.2.7

When I ran:

rails server

the Webrick server started, and I was able to view my getting started page. I was also able to continue with the tutorial a little ways. Then, I ran into some trouble with some missing/broken packages, and upgraded Ubuntu to version 12 in the process of trying to fix that issue.

Once I logged into Ubuntu version 12, I tried to continue with the tutorial. This time when I ran

rails server

This happened:

  create  
  create  app/controllers
  create  app/helpers
  create  app/models
  create  app/views/layouts
  create  config/environments
  create  config/initializers
  create  config/locales
  create  db
  create  doc
  create  lib
  create  lib/tasks
  create  log
  create  public/images
  create  public/javascripts
  create  public/stylesheets
  create  script/performance
  create  test/fixtures
  create  test/functional
  create  test/integration
  create  test/performance
  create  test/unit
  create  vendor
  create  vendor/plugins
  create  tmp/sessions
  create  tmp/sockets
  create  tmp/cache
  create  tmp/pids
  create  Rakefile
  create  README
  create  app/controllers/application_controller.rb
  create  app/helpers/application_helper.rb
  create  config/database.yml
  create  config/routes.rb
  create  config/locales/en.yml
  create  db/seeds.rb
  create  config/initializers/backtrace_silencers.rb
  create  config/initializers/inflections.rb
  create  config/initializers/mime_types.rb
  create  config/initializers/new_rails_defaults.rb
  create  config/initializers/session_store.rb
  create  config/initializers/cookie_verification_secret.rb
  create  config/environment.rb
  create  config/boot.rb
  create  config/environments/production.rb
  create  config/environments/development.rb
  create  config/environments/test.rb
  create  script/about
  create  script/console
  create  script/dbconsole
  create  script/destroy
  create  script/generate
  create  script/runner
  create  script/server
  create  script/plugin
  create  script/performance/benchmarker
  create  script/performance/profiler
  create  test/test_helper.rb
  create  test/performance/browsing_test.rb
  create  public/404.html
  create  public/422.html
  create  public/500.html
  create  public/index.html
  create  public/favicon.ico
  create  public/robots.txt
  create  public/images/rails.png
  create  public/javascripts/prototype.js
  create  public/javascripts/effects.js
  create  public/javascripts/dragdrop.js
  create  public/javascripts/controls.js
  create  public/javascripts/application.js
  create  doc/README_FOR_APP
  create  log/server.log
  create  log/production.log
  create  log/development.log
  create  log/test.log
  create  vendor/rails

I tried researching what was happening, and it looked like a result of Rails being an older version. I ran this:

rails --version

..and got this:

Rails 2.3.14

I thought that maybe, somehow Rails got downgraded or something, so I ran this:

gem install rails

and got this:

Successfully installed rails-3.2.7
1 gem installed
Installing ri documentation for rails-3.2.7...
Installing RDoc documentation for rails-3.2.7...

I figured that it must be fixed, so I tried things that Rails 3 should be able to do again, and got the same result as before, so I ran this:

rails --version

and got this:

Rails 2.3.14

I ran through everything a few more times, and kept getting the same results. I've tried researching why this could be happening, and so far, I'm not coming up with anything. It looks like I can install Rails 3, but it doesn't change that Ubuntu 12 thinks that Rails 2 is installed. It also reacts as if Rails 2 is installed, and nothing seems to change that.

Why would Ubuntu think that Rails 2 was installed, if it's telling me that Rails 3 was just installed?

Some additional details:

• I'm using Zsh Terminal.
• I'm using sudo where I need to, even if I didn't write it here
• I'm running Ubuntu in VMware Workstation 8
• I'm running VMware Workstation 8 in Windows 7
• I tried installing Ubuntu 12 in a brand new virtual machine, and I'm getting the same issue there.

Answer 1

Because you have one of the pre-built 2.3.14 rails packages from the repositories installed, in addition to Rails 3.2.7 installed via gem :-)

• Somehow, you installed one of these packages directly or as a dependency:

  rails - MVC ruby based framework geared for web application development
  ruby-rails-2.3 - MVC ruby based framework geared for web application development
  

• apt-cache show rails tells us that it is...Version: 2.3.14.1

• Starting from scratch, the following steps successfully install 3.2.7 (boringly detailed log available):

  sudo apt-get install rubygems
  sudo gem install rails
  #...wait for a while...
  $ rails --version
  Rails 3.2.7
  

• On your existing system, I recommend trying this to see if you can remove 2.3.14 and get 3.2.7 working as the default:

  sudo apt-get remove rails ruby-rails\*
  sudo apt-get autoremove
  sudo apt-get --reinstall install rubygems
  sudo gem install rails