Nginx Redirect (Rewrite) Old Domain To New Domain With HTTP 301

I've changed the domain name from long-domain-name-example.com to example.com which is shorter and easy to remember. How do I redirect old domain to new domain with "HTTP/1.1 301 Moved Permanently" status code under nginx web server running on Unix like operating systems?

Read answer to: "Nginx Redirect (Rewrite) Old Domain To New Domain With HTTP 301"