卸载
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
从新安装
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)
mac homebrew
原文：http://www.cnblogs.com/itwlg/p/5548271.html
