升级10.10 Yosemite 后，cocoapods 出现错误(解决方案)

RSMacBook-Pro:~ RS$ pod search jsonkit
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- xcodeproj/prebuilt/universal.x86_64-darwin14-2.0.0/xcodeproj_ext (LoadError)
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/ext.rb:6:in `rescue in <top (required)>'
    from /Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/ext.rb:3:in `<top (required)>'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj.rb:30:in `<top (required)>'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods.rb:2:in `<top (required)>'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/bin/pod:32:in `<top (required)>'
    from /usr/bin/pod:23:in `load'
    from /usr/bin/pod:23:in `<main>'

 一直想尝试新系统，由于担心bug会导致开发遇到一系列问题，一直忍住没有升级，前两天升级了，就立刻遇到这个问题。

无法对cocoapods进行操作，stackoverflow上有个解决方案，被多人转载，可惜didn't work for me. 于是我试着重新安装ruby，解决了

方案一：(适用于大多数人)

Open Xcode 6 打开Xcode 6 —— 系统偏好设置 —— 位置 —— 把命令行工具改为Xcode 6.0

卸载 cocoapods —— 重新安装 xcodeproj —— 重新安装 cocoapods

$ sudo gem uninstall cocoapods

$ sudo gem install xcodeproj

$ sudo gem install cocoapods
如果没有问题，运行pod --version 查看安装是否成功

如果，不幸的是，上述操作无法解决，就要和楼主一样了

1.更新rbenv        

$ curl -L get.rvm.io | bash -s stable

2.重新安装ruby

$ rvm install ruby 2.1.1

3.重新安装cocoapods

$ sudo gem install cocoapods