Q:

nginx reload config with multiple servers

I'm serving some demos in isolation like:
/demo1/-- nginx.conf
       |- index.html
       |- ...

#run
/demo1$ sudo nginx -c `pwd`/nginx.conf

and
/demo2/-- nginx.conf 
       |- index.html
       |- ...

#run
/demo2$ sudo nginx -c `pwd`/nginx.conf

now I have the following nginx processes:
$ ps aux | grep nginx
root      3434  0.0  0.0  85904  1340 ?        Ss   12:02   0:00 nginx: master process nginx -c /demo1/nginx.conf
nobody     3435  0.0  0.0  86316  2272 ?        S    12:02   0:00 nginx: worker process                                                 
root      5096  0.0  0.0  85904  1344 ?        Ss   11:21   0:00 nginx: master process nginx -c /demo2/nginx.conf
nobody     5097  0.0  0.0  86316  2272 ?        S    11:21   0:00 nginx: worker process 

I believe (tell me if I'm wrong) that if I reload the configuration this way:
$ sudo nginx -s reload

It will only deliver the message to the last master process that was spun.
How do I reload the configuration on a specific master process?
After reading the manpage I believe it has some to do with the -g option but I'm not sure how. Should I specify a static PID or something?
Here is my nginx.conf for reference
user nobody;
worker_processes  1;
events {
    worker_connections 1024;
}
http {
    include /etc/nginx/mime.types;
    server {
        listen      8000;
        location / {
            root    /demoX;
            index   index.html index.htm;
        }
    }
}

A:

You can use a signal to certain PID:
kill -QUIT 3434
Reload option is a reference to QUIT signal which reloads the config and spawn new worker.

