declare:tldr:999de

This command is used to declare and define a read-only shell variable in a script.

Here's a breakdown of the command:

• declare: This is a shell built-in command used to declare and set attributes for variables.
• -r: This is an option for the declare command, which sets the variable as read-only.
• ${variable}: This is the name of the variable you want to declare and define. It is enclosed in curly braces ({}) to help the shell interpret the variable name correctly.
• "${value}": This is the value assigned to the variable. It can be any valid value, and it is enclosed in double quotes ("") to preserve any spaces or special characters that might be part of the value.

So, when you run this command, it declares a read-only variable named ${variable} and assigns it the value ${value}. Once the variable is declared read-only, you won't be able to modify its value later in the script.