Open the Terminal application on a Mac and what do you see? A noble and worthy Unix “shell”, a program that geeks use to interact with the OS. Terminal uses the bash shell (for Bourne Again Shell. Created by Brian Fox, bash is based on the sh shell, which was invented by Stephen Bourne. Unix mavens love their word-play acronyms).
And now we have the Apple iOS, an OS X derivative that uses bits from the same kernel.