Я не могу переключить текущую версию Ruby:
➜ ~ rvm list rvm rubies ruby-1.9.2-p290 [ x86_64 ] ruby-1.9.3-p0 [ x86_64 ] ➜ ~ rvm use ruby-1.9.3-p0 RVM is not a function, selecting rubies with 'rvm use ...' will not work.