我的解决方案。
摘要 OS X 10.11 EI Capitan 安装Cocoapods 常规报错问题
OS X 10.11 EI Capitan 安装Cocoapods，报错， WTF！使用以下命令一句话解决:
sudo gem install -n /usr/local/bin cocoapods
更新Gem
sudo gem update --system -n /usr/local/bin
如果作者的方法没有帮你解决问题，请向下看。
网上的方案
OS X 10.11 安装Cocoapods 出现问题的解决方法
今天尝试用 Cocoapods安装个第三方库.. 输入pod install， 发现 command not find。
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
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..
