In many Oracle DBA interviews  many questions are asked relating to Unix. Here I have collected some common Interviews questions asked to a DBA relating to Unix environment. These questions are mostly asked for senior Oracle DBA positions. I have compiled these questions based upon the feedback I got from many candidates who have attended interviews in various MNC'

1. How do you see how many instances are running? 2. How do you automate starting and shutting down of databases in Unix?
 3. You have written a script to take backups. How do you make it run automatically every week?
 4. What is OERR utility?
 5. How do you see Virtual Memory Statistics in Linux?
 6. How do you see how much hard disk space is free in Linux?
7. What is SAR?
 8. What is SHMMAX?
9. Swap partition must be how much the size of RAM?
10. What is DISM in Solaris?

11. How do you see how many memory segments are acquired by Oracle Instances?12. How do you see which segment belongs to which database instances?
13. What is VMSTAT?
14. How do you set Kernel Parameters in Red Hat Linux, AIX and Solaris?
15. How do you remove Memory segments?
16. What is the difference between Soft Link and Hard Link?
17. What is stored in oratab file?
18. How do you see how many processes are running in Unix?
19. How do you kill a process in Unix?
 20. Can you change priority of a Process in Unix?