列出红宝石版本
console:~$ rvm list
rvm rubies
ruby-2.0.0-p481 [ i686 ]
# => - current
# =* - current && default
# * - default
尝试使用特定版本的红宝石
console:~$ rvm use 2.0.0
RVM is not a function, selecting rubies with 'rvm use ...' will not work.
You need to change your terminal emulator preferences to allow login shell.
Sometimes it is required to use `/bin/bash --login` as the command.
Please visit https://rvm.io/integration/gnome-terminal/ for a example.
source $HOME/.profile
或source $HOME/.bash_profile
在rvm可能已定义其init行的地方。