Kernel - Heart of the OS
you can Pick from 4 shells
1) Bourne Shell - The first Unix command processor (Bash Shell - Default Command interpreter
2) Korn Shell - Has extensions like a history thingy where you can recall your previous commands ( also know as the "K" shell )
3) C shell - designed for pro people ( C programing )
4) POSIX Shell - Standard
each shell has its own special shell commands, but the basic OS commands are generally the same for all four.
The default shell for our HP's is the Korn Shell