#!/bin/bash

SERIAL_NUM=$(cat /proc/cpuinfo | grep Serial | cut -d ' ' -f 2)
if [[ "$SERIAL_NUM" == "" ]]; then
    SERIAL_NUM=$(sudo dmidecode | grep UUID | cut -d ' ' -f 2)
elif [[ "$SERIAL_NUM" == "0000000000000000" ]]; then
    # RockPro64 returns 0s, so use eth0 mac
    MAC=$(cat /sys/class/net/eth0/address)
    SERIAL_NUM=$(echo "${MAC//:}")
fi

echo $SERIAL_NUM