Chapter 3. Overview of a Linux System

Table of Contents
3.1. Various parts of an operating system
3.2. Important parts of the kernel
3.3. Major services in a UNIX system
3.3.1. init
3.3.2. Logins from terminals
3.3.3. Syslog
3.3.4. Periodic command execution: cron and at
3.3.5. Graphical user interface
3.3.6. Networking
3.3.7. Network logins
3.3.8. Network file systems
3.3.9. Mail
3.3.10. Printing
3.3.11. The filesystem layout

"God saw everything that he had made, and saw that it was very good. " -- Bible King James Version. Genesis 1:31

This chapter gives an overview of a Linux system. First, the major services provided by the operating system are described. Then, the programs that implement these services are described with a considerable lack of detail. The purpose of this chapter is to give an understanding of the system as a whole, so that each part is described in detail elsewhere.