FAQ during interview for UNIX/LINUX system engineer/admin

I'm compiling a never_ending_list of questions that frequently asked during interview session for UNIX/LINUX system engineer/admin post. No, I'm not looking for new job right now or preparing for an interview, just want to make a list and share my experience. hopefully it could help others for their interview. even though you do all these tasks almost everyday, sometimes all the sudden your brain went blank during the session... dang!!! so be prepared!
you are most welcome to add yours in the comment!

here are the questions i've been asked, those that i can remember.
in no specific order:

1. Explain suid, sgid & sticky bit
2. What is sudo?
3. When you create a file in unix, by default what permissions will be applied to it? How do you change this setup?
4. Journaling filesystem? What is it?
5. What is /proc?
6. Explain steps to add new hard disks untill to mirror them
7. NFS export options/features/security
8. Autofs - Is it possible to mount the directory without cd into it?
9. What is stale file handle error in NFS?
10. What is the difference between UDP and TCP?
11. How do you list open files?
12. How to check number of files limit by kernel?
13. What is the difference between hard and soft mount?
14. Explain boot process
15. What is PAM?
16. What performance monitoring tools do you use?
17. Explain load average
18. What is ssh? How to setup trust between accounts/machines?
19. NIS administration/commands
20. How to limit certain users accessing certain machines?
21. How you troubleshoot slow performance?
22. Jumpstart & kickstart servers & process
23. Package management for linux & solaris - how to use them?
24. Solaris mirroring
25. What is zombie process?
26. Scripting skills, to automate certain jobs, cron
27. How do you perform changes on a few machines?
28. Xwindows options/features/security
.
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looking for the answers? No... you have to find the answers yourself :P