How to modify a global variable within a function in bash?

Question

I\'m working with this:

GNU bash, version 4.1.2(1)-release (x86_64-redhat-linux-gnu)

I have a script like below:

#!/bin/bas         


        

Answer 1

It's because command substitution is performed in a subshell, so while the subshell inherits the variables, changes to them are lost when the subshell ends.

Reference:

Command substitution, commands grouped with parentheses, and asynchronous commands are invoked in a subshell environment that is a duplicate of the shell environment