readonly name[=word]...

readonly -p

The variables whose names are specified shall be given the readonly attribute. The values of variables with the readonly attribute cannot be changed by subsequent assignment, nor can those variables be unset by the unset utility. If the name of a variable is followed by = word, then the value of that variable shall be set to word.

The readonly special built-in shall support the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.

When -p is specified, readonly writes to the standard output the names and values of all read-only variables, in the following format:

"readonly %s=%s\n", <name>, <value>

if name is set, and

"readonly %s\n", <name>

if name is unset.

The shell shall format the output, including the proper use of quoting, so that it is suitable for reinput to the shell as commands that achieve the same value and readonly attribute-setting results in a shell execution environment in which:

1.

Variables with values at the time they were output do not have the readonly attribute set.

2.

Variables that were unset at the time they were output do not have a value at the time at which the saved output is reinput to the shell.

When no arguments are given, the results are unspecified.