The UNIX System

The UNIX system consists of two main components:

  • Utilities

  • Kernel

Utilities are programs that can be executed. The programs who and date from the previous chapter are examples of utilities.

Commands are slightly different from utilities. The term utility refers to the name of a program, whereas the term command refers to the program and any arguments are specified to that program in order to change its behavior. For simple commands, the term command is sometimes used in place of the term utility.

The kernel is the heart of the UNIX system. It provides utilities with a means of accessing the computer's hardware. It also handles scheduling and executing commands.

When a computer is powered off, both the kernel and the utilities are ...

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