OS X 10.11 安装Cocoapods 出现问题的解决方法，10.11cocoapods

今天尝试用 Cocoapods安装个第三方库.. 输入pod install， 发现 command not find。 WTF！ 
估计是升级10.11后Cocoapods被干掉了。 
我输入 sudo gem install cocoa pods 之后，出现如下问题： 
ERROR:  While executing gem ... (Gem::DependencyError)    
Unable to resolve dependencies: cocoapods requires cocoapods-core (= 0.33.1), claide (~> 0.6.1), cocoapods-downloader (~> 0.6.1), cocoapods-plugins (~> 0.2.0), cocoapods-try (~> 0.3.0), cocoapods-trunk (~> 0.1.1), nap (~> 0.7) 
解决方法：sudo gem
update --system    但是出现了另一个错误： 

ERROR:  While executing gem ... (Errno::EPERM)

  
  Operation not permitted - /usr/bin/xcodeproj 
在Stackoverflow上找到了解决方法： 
在终端中输入：sudo nvram boot-args="rootless=0"; sudo reboot 然后你的电脑会重启 之后再输入 sudo gem install cocoapods -V  就可以了 不放心的话输入 pod
--version 0.37.2 //显示出版本就说明成功了 
但是之后我pod install的时候又花式出错 

[!] Unable to add a source with url `https://github.com/CocoaPods/Specs.git` named `master`.

You can try adding it manually in `~/.cocoapods/repos` or via `pod repo add`.

我尝试按提示的方法 

pod repo add master https://github.com/CocoaPods/Specs.git
然而还是有错.. 

[!] /usr/bin/git clone http://git.oschina.net/akuandev/Specs.git master

xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

最后的解决方法： 

sudo xcode-select -switch /Applications/Xcode-beta.app/Contents/Developers

后面的地址你可以打开Xcode显示包内容，找到那个文件夹拖到终端里面比较不容易错。 

CocoaPods 0.38.0.beta.2 is available.

To update use: `gem install cocoapods --pre`

[!] This is a test version we'd love you to try.

For more information see http://blog.cocoapods.org
and the CHANGELOG for this version http://git.io/BaH8pQ.
CocoaPods 0.38.0.beta.2 is available.

To update use: `gem install cocoapods --pre`

[!] This is a test version we'd love you to try.

For more information see http://blog.cocoapods.org
and the CHANGELOG for this version http://git.io/BaH8pQ.
最后终于修成正果.. 
至于一开始输入 sudo gem install cocoapods
没反应需要修改为淘宝镜像的问题，请百度Cocoapods参阅其它文章..