Wait for Reboot

wait_for_reboot() {
    cnt=0
    host=$1
    start=`date +%s`

    ping -c 1 -n -w 1 $host | grep "1 received" > /dev/null
    [ $? != 0 ] && status=down || status=up
    [ "$2" == "" ] && timeout=90 || timeout=$2

    echo -en "\nWaiting for target host \"$host\" to reboot."

    while true; do
        ping -c 1 -n -w 1 $host | grep "0 received" > /dev/null
        result=$?

        echo -n "."
        cnt=$((cnt+1))
        [ $result == 1 ] && sleep 1 || status=down

        [ $result == 1 ] && [ $status == "down" ] && {
            sleep 1
            end=`date +%s`
            echo -e "Done\n\nHost \"$host\" is back online, reboot time: $(format_time1 $[end-start])"
            break
        } || [ $cnt -ge $timeout ] && {
            echo -e "\nRemote host \"$host\" did not reboot. [timeout > $timeout]\n"
            break
        }
    done
}