countdown.sh

#!/bin/bash

echo "Countdown"

date1=$((`date +%s` + $1));
while [ "$date1" -ge `date +%s` ]; do
  echo -ne "$(date -u --date @$(($date1 - `date +%s`)) +%H:%M:%S)\r";
  sleep 0.1
done

# chmod +x countdown
# countdown 60