map $request_uri $new_uri {
    default DEFAULT;
    /shell http://shell.com;
    /lol http://lol.com;
}
map $request_uri $ret_code {
    default 301;
    /shell 301;
    /lol 302;
}

server {
    listen 80;
    server_name TestDomain.com www.TestDomain.com;

    location / {
        add_header X-request_uri $request_uri;
        add_header X-new_uri $new_uri;
        add_header X-return_code $ret_code;
        if ($new_uri = "DEFAULT") {
            return 301 https://ashfame.com$request_uri;
        }
        if ($ret_code = 301) {
            return 301 $new_uri;
        }
        if ($ret_code = 302) {
            return 302 $new_uri;
        }
    }
}

$ curl -I testdomain.com/lol
HTTP/1.1 301 Moved Permanently
Server: nginx/1.10.0 (Ubuntu)
Date: Sun, 22 Jan 2017 20:04:06 GMT
Content-Type: text/html
Content-Length: 194
Connection: keep-alive
Location: https://ashfame.com/lol
X-request_uri: /lol
X-new_uri: DEFAULT
X-return_code: 301