cheat sheets.

If you want Nginx to always use the "Host" header as you would for virtual
hosting, you can use _ as server_name as of 0.6.x. However there is a better way
which I recommend. Use the following directives to use host header instead of
server_name:
optimize_server_names off;
server_name_in_redirect off;

Signals
-------

TERM (15), INT (1)  Terminate the server immediately
QUIT (3)            Stop the server
HUP (1)             Configuration changes, start new workers, graceful stop of
                    old workers
USR1                Reopen log files
USR2                Upgrade the server executable
WINCH               Graceful Stop (parent process advise the children to exit)