Friend,

1.Stick to your basics.
2.Put only things that you have done in your company in your resume. Interviewers make it a point to ask things that you have done and how good you are at it (rather than what you don't know).
3.Prepare well on topics like Boot procedure,crontabs,Users and profile creation and OS installation.
4. If you don't know something be candid about it.
5. It's your attitude and willingness to learn that matters more than your knowledge.(What good is knowledge for if they feel u don't have the attitude to work!!)

And Don't worry about the size of your comapny's production environment.Your production environment(inside you...) is more important than that.

All the best.

HG