终端执行pod setup pod update 报错 -- [!] Failed to connect to GitHub to update the CocoaPods/Specs specs repo - Please check if you are offline, or that GitHub is down
1. 如果你的Ruby运行环境大于2.0.0的话可以升级cocoapods解决，查看当前ruby终端命令ruby -v
可以参考：http://blog.csdn.net/potato512/article/details/62235282
1、更新gem：sudo gem update --system
2、删除gem源：gem sources --remove https://ruby.taobao.org/
3、修改gem源：gem sources -a https://gems.ruby-china.org
4、查看gem源是否是最新的：gem sources -l
5、升级cocoapods：sudo gem install -n /usr/local/bin cocoapods --pre
6、查看升级后的cocoapods版本：pod --version
但是在修改gem源时会报错
Error fetching https://gems.ruby-china.org:
Errno::ECONNREFUSED: Failed to open TCP connection to localhost:8118 (Connection refused - connect(2) for "localhost" port 8118) (https://gems.ruby-china.org/specs.4.8.gz)
根据提示考虑到应该是自己使用ss代理的问题
使用：env|grep -i proxy查看自己的代理设置
http_proxy=http://localhost:8118
https_proxy=http://localhost:8118
使用：unset https_proxy
unset http_proxy
后 env|grep -i proxy查看自己的代理设置为空
再修改gem源：gem sources -a https://gems.ruby-china.org成功。
