#!/usr/bin/env bash

d=$((`date +%s` + $1));
echo "Countdown started $(date)"

while [ "$d" -ge $(date +%s) ]; do 
	_dt=$(($d - `date +%s`))
	days=$((_dt / 86400))
	echo -ne "\r${days}d $(date -u --date @$((_dt)) +%H:%M:%S) "; 
	sleep 0.1
done

echo -ne "\rCountdown finished $(date)\n"