# shellcheck shell=bash

source=$(realpath -m "$1")
target=$(realpath -m "$2")

if [[ -f "$target" ]]; then
  temp=$(mktemp)
  awk -F '=' 'NR==FNR{a[$1]=$0;next}($1 in a){$0=a[$1]}1' "$source" "$target" > "$temp"
  mv "$temp" "$target"
else
  mkdir -p "$(dirname "$target")"
  cp "$source" "$target"
fi

echo "Configuration file $target has been updated."