rubygems.rb cannot be loaded
<p>On Linux Mint 17.3, I upgraded from Ruby 1.9.2 to Ruby 2.3.0 using RVM, and now the 'gem' CLI and every Ruby program that uses gems are returning the following error:</p>

<p><code>&lt;internal:gem_prelude&gt;:1:in require': cannot load such file -- rubygems.rb (LoadError)
    from &lt;internal:gem_prelude&gt;:1:in</code>'`</p>

<p>I have tried reinstalling Ruby, switching to other versions (including back to 1.9.2), reinstalling RVM, and <code>rvm fix-permissions</code>, none of which have changed the error.</p>

<p>Any idea what's going on here?</p>

<p>EDIT: I was able to get CLI functionality back seemingly by repeatedly reinstalling 2.3.0 (<code>rvm reinstall</code> rather than uninstalling and reinstalling manually). However, programs that require gems are still breaking with the same error.</p>