title: Uninstalling and upgrading Ruby on a Mac without using RVM
body: <p>I recently decided to uninstall RVM from my system.  Some of the arguments made at <a href="https://github.com/sstephenson/rbenv#readme">this page</a> convinced me: </p>
  
  <p>Actually, what I decided, however, is that I don't want to worry about multiple versions of Ruby at all.  I just want to use version 1.9.2-p290 and not worry about anything else. When I run <code>ruby --version</code> on my Mac, though, it tells me I have version 1.8.7.  I have looked around for how to simply uninstall this Ruby from my Mac, but I haven't found anything, weirdly.  It seems that the only people who ever want to uninstall Ruby run linux and everyone using a Mac recommends RVM.</p>
  
  <p>How do I uninstall Ruby 1.8.7 from my Mac?  I'd like to move to version 1.9.2-p290 and I'd like to have only one version on my system.</p>