1) If experience is less than 3 years then generally you have to clear a written/online test.
2) Very basic aptitude questions, sql questions. unix questions, reasoning, programming ( C++/Java/C ).
3) If test cleared then face to face interview ( 1 - 2 rounds ).. Face to face will contain general programming questions like write a program for fibonacci, string functions etc. Lot of questions on unix if you are from unix background.
Prepare well for Unix, directory structure, grep,cd,sed, etc. If applying for support, SQL is a must. Pl/SQl is big advantage.