programming for unix environment

i have to make a menu based program to allow iusers to select the system information about their machine that they want. All i have been taught is how to enter commands at the command prompt like simple commands such as pwd and cd directory to change directory (not even sure if that is right). But i dont know how you get about writing a program for a unix system that works when you call it up and the user just runs it and uses it.

As you can probably tell i am a unix newbie and i would appreciate any help you guys to give me

you are not supposed to duplicate posts !!!

read the rules please.

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For menu based programs, use curses programming.
Get some online books for C Programming in the Unix Environment that should give a start with.