解决办法：
mac终端中输入
sudo vi /etc/hosts

Host Database

localhost is used to configure the loopback interface

when the system is booting. Do not change this entry.

127.0.0.1 localhost
255.255.255.255 broadcasthost

然后到后面：

GitHub Start

52.74.223.119 github.com
192.30.253.119 gist.github.com
54.169.195.247 api.github.com
185.199.111.153 assets-cdn.github.com
151.101.76.133 raw.githubusercontent.com
151.101.108.133 user-images.githubusercontent.com
151.101.76.133 gist.githubusercontent.com
151.101.76.133 cloud.githubusercontent.com
151.101.76.133 camo.githubusercontent.com
151.101.76.133 avatars0.githubusercontent.com
151.101.76.133 avatars1.githubusercontent.com
151.101.76.133 avatars2.githubusercontent.com
151.101.76.133 avatars3.githubusercontent.com
151.101.76.133 avatars4.githubusercontent.com
151.101.76.133 avatars5.githubusercontent.com
151.101.76.133 avatars6.githubusercontent.com
151.101.76.133 avatars7.githubusercontent.com
151.101.76.133 avatars8.githubusercontent.com

GitHub End

完整的 ：

Host Database

localhost is used to configure the loopback interface

when the system is booting. Do not change this entry.

127.0.0.1 localhost
255.255.255.255 broadcasthost

GitHub Start

52.74.223.119 github.com
192.30.253.119 gist.github.com
54.169.195.247 api.github.com
185.199.111.153 assets-cdn.github.com
151.101.76.133 raw.githubusercontent.com
151.101.108.133 user-images.githubusercontent.com
151.101.76.133 gist.githubusercontent.com
151.101.76.133 cloud.githubusercontent.com
151.101.76.133 camo.githubusercontent.com
151.101.76.133 avatars0.githubusercontent.com
151.101.76.133 avatars1.githubusercontent.com
151.101.76.133 avatars2.githubusercontent.com
151.101.76.133 avatars3.githubusercontent.com
151.101.76.133 avatars4.githubusercontent.com
151.101.76.133 avatars5.githubusercontent.com
151.101.76.133 avatars6.githubusercontent.com
151.101.76.133 avatars7.githubusercontent.com
151.101.76.133 avatars8.githubusercontent.com

GitHub End

~
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"/etc/hosts" [readonly] 28L, 971C

esc退出,:wq!强行储存退出，接着暗黄RVM
搞定！1