#!/bin/sh

set -e

[ -x /usr/lib/ubuntu-release-upgrader/release-upgrade-motd ] || exit 0

sleep_then_check() {
    # Sleep for up to an hour to spread the load of checking for updates on
    # the Ubuntu infrastructure
    sleep $(shuf -i 1-3600 -n 1)
    # Check to see whether there is a new version of Ubuntu available
    /usr/lib/ubuntu-release-upgrader/release-upgrade-motd
}

sleep_then_check &