Z:gnu-bash--6ad98d-Mark shell variables as unchan/en

Mark shell variables as unchangeable. Mark each NAME as read-only; the values of these NAMEs may not be   changed by subsequent assignment. If VALUE is supplied, assign VALUE before marking as read-only. Options: -a	refer to indexed array variables -A	refer to associative array variables -f	refer to shell functions -p	display a list of all readonly variables or functions, depending on           whether or not the -f option is given An argument of `--' disables further option processing. Exit Status: Returns success unless an invalid option is given or NAME is invalid.