How do get any exit code in bash when running a script inside a script?

Question

I am trying to run a script where inside I run another script, after it has run I want to retrieve the exit code and do something with it but I only get 0 every time.

I also tried different approaches with sourcing it or wrapping the command in a function and had also given both execution rights with chmod -x .

a.sh

#!/usr/bin/env bash

mkdir data
mkdir -p data/test

b.sh

#!/usr/bin/env bash

set -x

(bash a.sh) &
pid=$!

wait $pid
exitCode=$?

echo $pid
echo $exitCode

Result with bash b.sh :

+ pid=7399
+ wait 7399
+ bash a.sh
mkdir: data: File exists
+ exitCode=0
+ echo 7399
7399
+ echo 0
0

Result with bash a.sh :

mkdir: data: File exists (no exit code)

Result with mkdir data :

mkdir: data: File exists (exit code 1)

I know I can do mkdir -p data but this is just a test to get any exit code that I can work with later in my script.

Bash version: GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin18)

Answer 1

Solved it by using: set -e

Reference: https://ss64.com/bash/set.html

This enables immediately exiting when something went wrong. In my case the second command returned 0 and that's why I got 0 every time.