MAC上更新Ruby失败解决办法

尝试用RVM升级Ruby

http://blog.csdn.net/lissdy/article/details/9191351

如果碰到下面问题

Searching for binary rubies, this might take some time.

No binary rubies available for: osx/10.11/x86_64/ruby-2.2.4.

Continuing with compilation. Please read ‘rvm help mount‘ to get more information on binary rubies.

Checking requirements for osx.

Installing requirements for osx.

Updating system.......

Error running ‘requirements_osx_brew_update_system ruby-2.2.4‘,

先运行下面命令，再安装：

rvm autolibs read-only