Korn Shell Programming by Example

readonly

Official Description

Defines or displays aliases.

Syntax

readonly [name[=value ...]]

Options

-p precedes the output with readonly.

Oddities

It's similar to typeset -r.

The -p option is available in ksh93 and beyond.

Example

$ readonly –p                # Displays read-only variables (none yet)
$
$ readonly x=17              # Create read-only variable
$
$ readonly –p                # Display
readonly x=17
$
$ x=24                       # Try to change read-only variable
/bin/ksh: x: is read only    # No can do
$