#!/bin/sh
old_timestamp="$(</etc/local.d/.ntpsync)"
new_timestamp="$(date +%s)"
if [ "$((new_timestamp-old_timestamp))" -gt 604800 ]; then
    ntpdate -b pool.ntp.org
    hwclock --systohc --utc
    echo "$new_timestamp" > /etc/local.d/.ntpsync
fi