If you visit gist.github.com in China, you might find:
dig +trace gist.github.com
, found the A record of gist.github.com was returned by a generic top level domain (gTLD) name server, which was not the expected.
Open your terminal, sudo vi /etc/hosts
, add the following line, then save:
192.30.253.119 gist.github.com
Here you go: