readonly mark KornShell variable as read-only	KornShell Built-in
	SYNOPSIS DESCRIPTION   Options DIAGNOSTICS PORTABILITY NOTE SEE ALSO

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SYNOPSIS

readonly [-p] [name[=value]...]

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DESCRIPTION

readonly prevents subsequent changes in the value of any of the name arguments. Parameters of the form

name=value

assign value to the KornShell variable name as well as marking name read-only. If readonly is called without arguments it lists, with appropriate quoting, the KornShell variables set as read-only. The following format is used:

Variable="value"

This format is suitable for reading by a shell script, but to ensure the portability of read-only access, the -p option should be used.

Options

-p

displays read-only variables in the format:

readonly name=value

This ensures portability when this output is used as input to a shell.

Note:

Normally, this output is captured in a file which is then sourced to reproduce the current environment. Because trying to change a read-only variable fails with an error, you can't successfully source the output unless you go to a new shell.

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DIAGNOSTICS

Possible exit status values:

0

Successful completion.

1

An attempt to give read-only status to a variable which is already read-only.

2

Failure due to invalid command line argument.

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PORTABILITY

POSIX.2. x/OPEN Portability Guide 4.0.

readonly is a built-in command of the Bourne Shell and KornShell on UNIX systems.

The behavior of readonly when called with no arguments is an extension to the POSIX and XPG standards.

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NOTE

This is a special built-in command of the MKS KornShell.

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SEE ALSO

Commands:

alias, sh, typeset