一个cocoapods问题的解决，希望能帮助到遇到类似情况的人

之前10.7的系统上运行过cocoapods没有问题。现在系统版本升级到了10.9，尝试使用cocoapods遇到问题，报告了类似下面的错误：

Psych::SyntaxError - (/Users/psteinacher/.cocoapods/repos/master/CocoaPods-version.yml): mapping values are not allowed in this context at line 3 column 4
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/psych.rb:205:in `parse'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/psych.rb:205:in `parse_stream'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/psych.rb:153:in `parse'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/psych.rb:129:in `load'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/psych.rb:299:in `block in load_file'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/psych.rb:299:in `open'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/psych.rb:299:in `load_file'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.28.0/lib/cocoapods/sources_manager.rb:248:in `version_information'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.28.0/lib/cocoapods/sources_manager.rb:209:in `repo_compatible?'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.28.0/lib/cocoapods/sources_manager.rb:268:in `master_repo_functional?'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.28.0/lib/cocoapods/command.rb:40:in `parse'
/Library/Ruby/Gems/2.0.0/gems/claide-0.4.0/lib/claide/command.rb:179:in `parse'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.28.0/lib/cocoapods/command.rb:39:in `parse'
/Library/Ruby/Gems/2.0.0/gems/claide-0.4.0/lib/claide/command.rb:211:in `run'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.28.0/lib/cocoapods/command.rb:52:in `run'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.28.0/bin/pod:24:in `'

经过多方尝试，发现执行如下的命令可以解决问题：

$ sudo rm -fr ~/.cocoapods/repos/master
$ pod setup

最后推荐一个xcode插件，可以很方便的使用cocoapods。

CocoaPods for Xcode
非常方便的Xcode pods插件。可以很方便的在Xcode通过pods安装各种objective-c第三方库，省去以前还要手动去跑pods命令行的麻烦；此外，还支持通过cocoaDocs来安装库文档。唯一的遗憾是，它目前只支持Xcode5，4版本还用不了。
项目地址：https://github.com/kattrali/cocoapods-xcode-plugin

Enjoy it!