Chapter 3. What Is the Shell?

In this chapter you'll learn what the shell is and what it does.

The Kernel and the Utilities

The Unix system is itself logically divided into two pieces: the kernel and the utilities (see Figure 3.1).

The Unix system.

Figure 3.1. The Unix system.

The kernel is the heart of the Unix system and resides in the computer's memory from the time the computer is turned on and booted until the time it is shut down.

The utilities, on the other hand, reside on the computer's disk and are only brought into memory as requested. Virtually ...

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