We are allowed to use our own custom domain with Github Pages.
For example, I have my page: http://example.com which points to http://username.github.io/project
But now I need to create a subdomain for another folder inside my repo. like
http://zuckerberg.example.com ---> which points to ---> http://username.github.io/project/zuckerberg
Is it possible to accomplish on github? I can't find any documentation about subdomain of custom domains :/
I found this so far https://help.github.com/articles/user-organization-and-project-pages but it's really confusing
You will not be able to point a custom subdomain to http://username.github.io/project/zuckerberg. You will have to point it to another project http://username.github.io/otherproject Some more documentation https://help.github.com/articles/tips-for-configuring-a-cname-record-with-your-dns-provider and https://help.github.com/articles/about-custom-domains-for-github-pages-sites
Examble of real-world CNAME files
The username.github.io repository has a CNAME file with the domain www.domain.com.
- The User Pages site at username.github.io redirects to www.domain.com.
- The Project Pages site at username.github.io/project redirects to www.domain.org/project.
来源：https://stackoverflow.com/questions/25479210/subdomain-of-custom-domain-on-github-pages