server { server_name example.com; return 301 $scheme://www.example.com$request_uri; }
server { server_name “~^(?!www.).*” ; return 301 $scheme://www.$host$request_uri; }
server { server_name www.example.com; return 301 $scheme://example.com$request_uri; }
server { server_name “~^www.(.*)$” ; return 301 $scheme://$1$request_uri ; }
