Passing arguments by reference

Question

I want to ask if it is possible to pass arguments to a script function by reference:

i.e. to do something that would look like this in C++:

Answer 1

Bash doesn't have anything like references built into it, so basically the only way you would be able to do what you want is to pass the function the name of the global variable you want it to modify. And even then you'll need an eval statement:

boo() {
    eval ${1}="new"
}

SOME_VAR="old"
echo $SOME_VAR # old
boo "SOME_VAR"
echo $SOME_VAR # new

I don't think you can use indirect references here because Bash automatically accesses the value of the variable whose name is stored in the indirect reference. It doesn't give you the chance to set it.