title: Installing Gems without rvm, as root, with explicit version of ruby
body: <p>I've decided to get rid of rvm, and I'm having trouble compiling a gem with my new version of ruby 1.9.2. The gem requires 1.9.2, I have it, yet says it can't install without, so the error messages makes no sense.</p>
  
  <p>How can I explicitly tell the gem to compile with said version of ruby?</p>
  
  <pre><code>Gem::InstallError: linecache19 requires Ruby version &gt;= 1.9.2.
  An error occured while installing linecache19 (0.5.12), and Bundler cannot continue.
  Make sure that `gem install linecache19 -v '0.5.12'` succeeds before bundling.
   apps2 ~/projects/sms/apps2/apps2_admin $ ruby -v
  ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-darwin10.8.0]
   apps2 ~/projects/sms/apps2/apps2_admin $ which ruby
  /usr/local/bin/ruby
  </code></pre>