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

I had a similar problem, when I wanted to automatically remove temp files I had created. The solution I came up with was not to use command substitution, but rather to pass the name of the variable, that should take the final result, into the function. E.g.

#! /bin/bash

remove_later=""
new_tmp_file() {
    file=$(mktemp)
    remove_later="$remove_later $file"
    eval $1=$file
}
remove_tmp_files() {
    rm $remove_later
}
trap remove_tmp_files EXIT

new_tmp_file tmpfile1
new_tmp_file tmpfile2

So, in your case that would be:

#!/bin/bash

e=2

function test1() {
  e=4
  eval $1="hello"
}

test1 ret

echo "$ret"
echo "$e"

Works and has no restrictions on the "return value".