目前正在运行Yosemite并且无法更新到ruby 2.1.4，请参阅下文。
Guidos-MacBook-Pro:~ Guido$ rvm install 2.1.4
Searching for binary rubies, this might take some time.
No binary rubies available for: osx/10.10/x86_64/ruby-2.1.4.
Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
Checking requirements for osx_brew.
/usr/local/bin/brew: /usr/local/Library/brew.rb: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby: bad interpreter: No such file or directory
/usr/local/bin/brew: line 26: /usr/local/Library/brew.rb: Undefined error: 0
ERROR: '/bin' is not writable - it is required for Homebrew, try 'brew doctor' to fix it!
Requirements installation failed with status: 1.
答案 0 :(得分：0)
因此，当我离开电脑几个小时后又回来时，我发现问题是在我将操作系统更新到优胜美地之后，Homebrew被打破了。以下是解决方案的链接http://ryantvenge.com/2014/09/ruby-homebrea-yosemite/。如果不起作用，请参阅下面的命令。
修复Homebrew：
cd /System/Library/Frameworks/Ruby.framework/Versions
sudo ln -s当前1.8
brew更新
sudo rm 1.8
更新为ruby 2.1.4：
rvm install 2.1.4
rvm使用2.1.4