I had left an Ubuntu 9.10 LiveCD session running, and had installed openssh-server and set the password for ubuntu by running

passwd

so I was able to ssh into the session later. However, I wanted to restart back into my normal session, which requires restarting. I think it's possible to pass some argument to shutdown so that it doesn't halt gracefully, but there should be an easier way. Indeed, I found a useful clue at http://www.pendrivelinux.com/ubuntu-remove-the-prompt-to-eject-cd/. Specifically, the bit about S*casper. I was able to modify /etc/rc0.d/S89casper, and comment out a line that said

read x < /dev/console

which appears to have work, as I managed to ssh into my normal session. Not bad. It may be worth mentioning that the boot order for my PC does not include the CD drive - that is selected via a boot menu, so when the computer restarts it will not boot from the CD again, which I guess is why that `feature' is there.

Also, after searching a bit, it appears that this sort of thing is a common issue for people using USB drives. However, a lot of solutions seem to recommend simply deleting the file, rather than simply uncommenting the irritating bit.