how to tell graphical Emacs to shutdown cleanly from tty1?

[Tom Roche]

Lately I run GNU Emacs mostly as GUI on X/tty7 (which I'll call "the desktop" 
as opposed to emacs-desktop) on one of my Debian laptops. Occasionally the 
desktop hangs, in which case I usually can goto tty1 and `sudo shutdown 
-whatever now`. Unfortunately this does not seem to cause Emacs to shut down as 
cleanly as I'd like: I'd like Emacs to (e.g.) save any unsaved buffers and save 
its emacs-desktop, but that doesn't seem to get done. (Am I missing something?)

So I'm thinking that, in this usecase, I should utter something from tty1 
(before `shutdown`) to tell Emacs to shutdown cleanly ... but I don't know what 
to say. How to do this?

TIA, Tom Roche <Tom_Roche@pobox.com>