IP address from store ID

ohjeez.sh

declare -a ip_address

for i in {3..1}; do
  # bash fails when using ${var: -n} to trim strings if the number is greater
  # than the number of characters. So this uses ${#var} to test the length
  # huehuehue
  last_3=${store_id: ${#store_id}<3?0:-3}

  if [ $last_3 -gt 255 ]; then
    last_3=${last_3: -2}
    store_id=${store_id::-2}
  else
    # head -c-n doesn't fail as badly as bash
    store_id=$(echo $store_id | head -c-3)
  fi

  ip_address[$i]=$last_3;
done

ip_address="10.$(( 10#${ip_address[1]} )).$(( 10#${ip_address[2]} )).$(( 10#${ip_address[3]} ))"
echo $ip_address