Ruby problem

[Ryan Schmidt]

On Mar 8, 2012, at 16:21, Phil Dobbin wrote:

> For some while now I've used rvm installed in $HOME to manage my Ruby
> stuff but every time I install anything from Mac Ports the Ruby version
> gets switched back to the 1.8.7. in /opt/local (can be a pain if I
> forget to switch it back & the first time I notice is when it errors
> because they are no rubygems installed in /opt/local).
> 
> Short of uninstalling Ruby & Vim is there any way 'round this to stop it
> happening?

What, exactly, happens? What does it mean, "the Ruby version gets switched"?