mac更新ruby

curl -L get.rvm.io | bash -s stable
source ~/.bashrc  
source ~/.bash_profile
#查看当前ruby版本  
ruby -v  
ruby 1.8.7  
#列出已知的ruby版本  
rvm list known  
#安装ruby 2.3.0
rvm install 2.3.0
#Error running 'requirements_osx_brew_update_system ruby-2.3.0',showing last 15 lines of /Users/liuman/.rvm/log/1471250320_ruby-2.3.0/update_system.log
rvm autolibs read-only # read more here:https://rvm.io/rvm/autolibs
rvm install ruby