Fix: MacOS needs bash 5.x from homebrew

Author: bnmnetp

docs/source/running.rst

@@ -22,6 +22,10 @@ Before running the setup script, you need:
   - The script must run from a WSL2 terminal (Ubuntu, Debian, etc.)
   - Do not use PowerShell or Command Prompt
 
+- **bash** (Linux and macOS have this by default, but...)
+
+  - The script uses features of bash introduced in version 5.0 so make sure you have a compatible version (Linux typically has this, macOS may require installing a newer version via Homebrew)
+
 **Optional:**
 
 - **Git** - Only needed if you want to clone book repositories

init_runestone.sh

@@ -463,6 +463,12 @@ validate_prerequisites() {
     print_header "Validating Prerequisites"
 
     detect_platform
+    BASH_VERSION=$(bash --version | head -n 1 | awk '{print $4}')
+    if [[ "$BASH_VERSION" < "5.0" ]]; then
+        print_warning "You are using an old version of Bash ($BASH_VERSION). It is recommended to install a newer version via Homebrew: brew install bash then rerun the script with the new bash: /usr/local/bin/bash init_runestone.sh"
+        exit
+    fi
+
     check_docker
     check_docker_compose
     check_docker_group