We recommend that the reader study this chapter before beginning a UNIX terminal session, for it is here that the fundamental features of the UNIX operating system are introduced and compared to those of Open-VMS. Section 2.1 provides the new UNIX user with an understanding of the basic functions of the UNIX kernel, the various UNIX utilities and tools, and the user interface, as well as of how these compare with the structure of OpenVMS.

Section 2.1.1 introduces the subject of process creation, which requires more detailed consideration. Users may run UNIX commands simultaneously as separate processes created by the shell. Understanding the interrelationships among these processes is a prerequisite to understanding how to use commands effectively. You may synchronize processes so that the output of one is used as input for the next, a procedure known as piping (Section 2.1.2). You may also easily redirect input and output between files and processes (Section 2.1.3).

Section 2.2 introduces the format of commands. Since many commands involve the manipulation of files, this section also discusses file and directory naming. Section 2.2.1 discusses what happens if you use an incorrect command syntax.

Section 2.3 introduces the concept of a UNIX file system and compares it to an OpenVMS physical device. This section also introduces the different types of UNIX files.

Section 2.4 introduces the concept of metacharacters, which perform special functions in command interpretation by the various...