Linux in a Nutshell, Fifth Edition

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Chapter 6: The Bash Shell and Korn Shell

This is the Title of the Book, eMatter Edition

Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

• Syntax

• Functions

• Variables

• Arithmetic expressions

• Command history

• Job control

• Command execution

• Restricted shells

• Built-in commands

http://www.gnu.org/software/bash/bash.html provides information about the Bash

shell, as does http://cnswww.cns.cwru.edu/~chet/bash/bashtop.html. http://www.

kornshell.com provides considerable information about the Korn shell. See also

Classic Shell Scripting, Learning the Korn Shell, and Learning the bash Shell (all

from O’Reilly).

All references in this chapter to the Bash shell are for Bash Version 3. Many of the

features listed for ksh93 are found only in the version available from AT&T

Research.

Overview of Features

The Bash and Korn shells provide the following features:

• Input/output redirection

• Wildcard characters (metacharacters) for filename abbreviation

• Shell variables and options for customizing your environment

• A built-in command set for writing shell programs

• Shell functions, for modularizing tasks within a shell program

• Job control

• Command-line editing (using the command syntax of either vi or emacs)

• Access to previous commands (command history)

• Integer arithmetic

• Arrays and arithmetic expressions

• Command-name abbreviation (aliasing)

ksh93 and Bash (but not ksh88) have the ...