readonly

Create or modify read-only variables within a shell script, preventing the variable from being changed by subsequent commands. This is useful when you want to ensure that a variable retains a constant value throughout the execution of a script. More information: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#readonly.

Create a read-only variable:

readonly {{variable_name}}={{value}}

Mark a variable as read-only:

readonly {{existing_variable}}

[p]rint the names and values of all read-only variables to stdout:

readonly -p