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Unix in a Nutshell, 4th Edition
book

Unix in a Nutshell, 4th Edition

by Arnold Robbins
October 2005
Intermediate to advanced
908 pages
46h 42m
English
O'Reilly Media, Inc.
Content preview from Unix in a Nutshell, 4th Edition

Discipline Functions (ksh93 Only)

Along with structured variables, ksh93 introduces discipline functions . These are special functions that are called whenever a variable’s value is accessed or changed. For a shell variable named x, you can define the following functions:

x.get

Called when x’s value is retrieved ($x).

x.set

Called when x’s value is changed (x=2).

x.unset

Called when x is unset (unset x).

Within the discipline functions, special variables provide information about the variable being changed:

.sh.name

The name of the variable being changed.

.sh.subscript

The subscript of the array element being changed.

.sh.value

The value of the variable being assigned or returned. Changing it within the discipline function changes the value that is actually assigned or returned.

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Publisher Resources

ISBN: 0596100299Errata Page