防火墙屏蔽了github.com

mac电脑升级导致brew不可用。重新安装brew，发现GFW把github屏蔽无法访问。
解决方法：
访问http://ipaddress.com/ 查询到github.com的真实ip。然后编辑/etc/hosts，将真实ip与域名映射。

#wulong: get real address from http://ipaddress.com/192.30.253.112  https://github.com192.30.253.112  http://github.com151.101.12.249  https://github.global.ssl.fastly.net

然后运行安装brew.

 /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" 

 
卸载brew命令：

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"