FreeBSD® Unleashed

Introducing the Shell

The UNIX shell is the command-line interface between the user and the operating system kernel. If you have worked with MS-DOS, you can think of the DOS prompt as being the same thing. In a looser sense, you could also think of the Windows or Macintosh desktop as being a shell. The shell acts like a translator—translating human language into machine language that the kernel can understand. The shell also translates machine language from the kernel into language that humans can understand. Figure 8.1 shows the relationship between the system hardware, the kernel, and the shell.

Figure 8.1. Relationship between hardware, kernel, and shell.

We will cover the role of the kernel in detail in Chapter 17, “Kernel Configuration.” ...