Could not find rails (>= 0) amongst [] (Gem::LoadError)

Question

After installing rvm, updating .gmrc file, updating rubygems and running gem install rails -v ">=3.1.0rc", I now seem to have a complete mess:

$ rails -v
/usr/local/lib/site_ruby/1.8/rubygems/dependency.rb:247:in `to_specs': Could not find rails (>= 0) amongst [] (Gem::LoadError)
    from /usr/local/lib/site_ruby/1.8/rubygems/dependency.rb:256:in `to_spec'
    from /usr/local/lib/site_ruby/1.8/rubygems.rb:1182:in `gem'
    from /var/lib/gems/1.8/bin/rails:18

---

myhome@myhome-mini:~$ gem env

RubyGems Environment:
  - RUBYGEMS VERSION: 1.6.2
  - RUBY VERSION: 1.9.2 (2011-02-18 patchlevel 180) [i686-linux]
  - INSTALLATION DIRECTORY: /home/myhome/gems
  - RUBY EXECUTABLE: /home/myhome/.rvm/rubies/ruby-1.9.2-p180/bin/ruby
  - EXECUTABLE DIRECTORY: /home/myhome/gems/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-linux
  - GEM PATHS:
     - /home/myhome/gems
     - /usr/lib/ruby/gems/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
     - "gemhome" => "/home/myhome/gems"
     - "gempath" => ["/home/myhome/gems", "/usr/lib/ruby/gems/1.8"]
  - REMOTE SOURCES:
     - http://rubygems.org/

Answer 1

I've had a similiar problem. Not sure if that helps you, but you might try to install gems with rvmsudo gem install [gemname] instead of just doing gem install [gemname] or sudo gem install [gemname].

I try to explain this a bit because of the upvotes:
This basically is a path issue. If you set up gems via gem install, they mostly likely will be in another directory (e.g. /usr/local/) compared to gems set up via bundler (where you can override it with --path). Using sudo may also set them up into another directory since sudo starts a subshell which has a different environment then. This is why you have rvmsudo.

If you want to see the differences, compare $PATH, $GEM_HOME, $GEM_PATH and $BUNDLE_PATH when echoing directly, with sudo and with rvmsudo.