Chapter 1. bash Basics

Since the early 1970s, when it was first created, the UNIX operating system has become more and more popular. During this time it has branched out into different versions, and taken on such names as Ultrix, AIX, Xenix, SunOS, and Linux. Starting on minicomputers and mainframes, it has moved onto desktop workstations and even personal computers used at work and home. No longer a system used only by academics and computing wizards at universities and research centers, UNIX is used in many businesses, schools, and homes. As time goes on, more people will come into contact with UNIX.

You may have used UNIX at your school, office, or home to run your applications, print documents, and read your electronic mail. But have you ever thought about the process that happens when you type a command and hit RETURN?