UNIX and the UNIX look-alike system Linux both have something for everyone. For the everyday user, these are friendly systems that offer a huge array of commercial and free software, including a free office suite. For the programmer, UNIX and Linux are ideal for collaborative development of software because they offer powerful tools and utilities. For the system administrator,
UNIX and Linux contain time-tested and leading-edge tools for networking and multiuser management. In this book, you learn UNIX through the eyes of Linux. Linux is a modern operating system that has generated significant interest among all kinds of computer users—from general users to computer professionals. Also, it is a popular server system on the Web and in businesses. If you use Google to find something on the Internet, you are using a Linux Web server. This chapter introduces you to operating systems in general and then explains the UNIX and Linux operating systems in particular. You also get an introduction to UNIX/Linux commands and command-line editing. As a variant of UNIX, Linux runs on PCs with Intel-type processors, but uses the same file systems and commands as other UNIX versions. Linux can be run from an individual PC workstation or as a server operating system that is accessed through a network. When you access it through a network, you might use an old-fashioned UNIX terminal, a modern UNIX or Linux workstation, or aWindows-based workstation. Several versions of Linux are