Terminal/Console no longer work


Help! This is terrible. And probably one of the dumbest things I've ever done.
Last night, I was messing around in the Terminal app, and just to see what happened, I typed "logout". It gives me the message "Process Completed". I smiled a little, turned off the computer, and went to bed. Here I come again today, open up Terminal. "Process Completed". Oh no! Opening a new shell doesn't do anything. I've even logged in as ">console". Input the username and password, and it just kicks me right back out to the OS X login screen. Does this for both my user and the root user. Anyone know how to fix this? Or have any suggestions at all?
I think you're the victim of a meaningless coincidence. Log in normally, open up Terminal and change the default shell (in preferences) to csh or sh--there's some evidence that tcsh gets corrupted very easily (search the forums for "tcsh" for more on that). If that works, then you can probably get tcsh back by deleting it and reinstalling it--that topic's been covered elsewhere, too.

I don't think that typing logout should have any ill effects--I can't recall, but I'm pretty sure I've done that. Turning off your computer without shutting down properly, of course, could have such effects, but I assume you didn't mean "turned off the computer" that way.