Does the iPhone have a command prompt?

Hi,

I have some quick general technical questions. Thanks for reading and all of your help!

1. Is the iPhone a Debian derivative like MacOS?
2. Is there a command prompt on the iPhone?
3. Can I install linux applications on the iPhone?
4. Can I compile C applications on the iPhone?
5. Are their any emulators on the iPhone?
6. If I jailbreak will any upcoming patches render my new phone/computer useless?

Thanks again!
Will

Welcome to the forum!
You should use the search function and do some basic reading first. Here is a good start:
http://www.hackint0sh.org/forum/f127/56076.htm
You'll find a link in post #1 with a lot of basic explanation. Follow the link there is more information on our member secretmrx's site.