转载自:http://blog.csdn.net/liuyujinglove/article/details/40582197
http://blog.csdn.net/dqjyong/article/details/37958067
大概步骤如下：
Open Xcode 6
Open Preferences
Click theLocationstab
Change theCommand Line Toolsversion toXcode 6.0
Uninstallcocoapods
a.$ sudo gem uninstall cocoapods
Installxcodeproj
a.$ sudo gem install xcodeproj
Installcocoapods
a.$ sudo gem install cocoapods
$ pod --version
如果你执行到第6步：sudo gem install xcodeproj 成功，但是到第七步：$ sudo gem install cocoapods时失败，错误信息如下：
ERROR:Could not find a valid gem 'cocoapods' (>= 0), here is why:Unable to download data from https://rubygems.org/ - Errno::ETIMEDOUT: Operation timed out - connect(2) (https://rubygems.org/latest_specs.4.8.gz)ERROR:Possible alternatives: cocoapods
意识是说在官方源中找不到我们需要的源，这时怎么办呢，网上找到一篇博客，这样做的，切换官方源，也即是改变源的获取地址
这时候我们需要改变 gem source, 参考[4], [5]。需要在终端中执行如下命令:
$ gem sources -l $ gem sources --remove https://rubygems.org/ $ gem sources -a https://ruby.taobao.org/ $ gem sources -l
接下来输入以下命令：
$ pod setup This processwilllikely take a while as this command clones the CocoaPods Specs repository into ~/.cocoapods/ on your computer. []
至此CocoaPods安装完毕。
注：如果漏掉 "$ pod setup" 命令，而直接执行"$ pod init"
会有类似以下的error信息：
$ pod init Setting up CocoaPods master repo [!] /usr/bin/git clone 'https://github.com/CocoaPods/Specs.git' master --depth= Cloning into 'master'... error: RPC failed; result=, HTTP code = fatal: The remote end hung up unexpectedly /Library/Ruby/Gems/2.0./gems/claide-0.6./lib/claide/command.rb::in `handle_exception': undefined method `verbose?' for nil:NilClass (NoMethodError) from /Library/Ruby/Gems/2.0./gems/claide-0.6./lib/claide/command.rb::in `rescue in run' from /Library/Ruby/Gems/2.0./gems/claide-0.6./lib/claide/command.rb::in `run' from /Library/Ruby/Gems/2.0./gems/cocoapods-0.33./lib/cocoapods/command.rb::in `run' from /Library/Ruby/Gems/2.0./gems/cocoapods-0.33./bin/pod::in `<top (required)>' from /usr/bin/pod::in `load' from /usr/bin/pod::in `<main>' "
以上操作步骤完成后在进行：
$ sudo gem install cocoapods
这时就成功了！
剩下的就是和以前的一样在工程目录下，建Podfile，执行pod install，打开xworkspace等，顺利完成！！！
参考博客：http://www.cnblogs.com/cwgk/p/3370949.html