步骤如下：

rvm install ruby-2.2

 但是，但是竟然报错了，具体我忘记额，但是是权限和brew的问题，那么我又转向修复brew：

 

 

// 清理原来brewrm -rf /usr/local/Cellar /usr/local/.git && brew cleanup // 安装 ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" // 检查有无问题 brew doctor

 

brew解决后，我赶紧去试试rvm install ruby-2.2,但是提示：

 

Already installed ruby-2.2.4.To reinstall use:    rvm reinstall ruby-2.2.4

 

OK，换成rvm reinstall ruby-2.2.4，成功,再去试试安装cocoapods

 

sudo gem install -n /usr/local/bin cocoapods --pre 关键命令:

$ rvm autolibs read-only # read more here: https://rvm.io/rvm/autolibs $ rvm install ruby # or any version you want