Chapter 9. Working with the POSIX Shell and Job Control

Chapter Syllabus

9.1 POSIX Shell Capabilities

9.2 File Name Completion

9.3 History and Reentering Commands

9.4 Command Line Editing

9.5 Substitution

9.6 Setting Terminal Parameters

9.7 Job Control

The shell is an interactive program that gets user input, interprets it, and then takes necessary action accordingly. It acts like a command interpreter for the user. As soon as a command is received from a user, the shell looks for a matching intrinsic command and executes it. If it does not find an intrinsic command, it searches for a disk file corresponding to the command and executes it. During this process it substitutes any variables and other commands listed in the command line. It also handles I/O redirection and can execute batch files containing other UNIX commands and control structures.