Linux bash Timer

问题

Ok, stupid newbie question here. I thought I was making a countdown timer. This is supposed to count down from 5 and once it is at 0 then execute the echo "time is up clown" then end. What am I doing wrong here?

seconds=5
date1=$((`date +%s` + $seconds)); 
while [ "$date1" -ne `date +%s` ]; do 
  if (!$date1 -lt ((`date +%s` + $seconds)+1)); then
     echo "time is up clown";
  break;
  fi;
  echo -ne "$(date -u --date @$(($date1 - `date +%s` )) +%H:%M:%S)\r";
done

回答1:

#!/bin/bash
SECS=5
while [[ 0 -ne $SECS ]]; do
    echo "$SECS.."
    sleep 1
    SECS=$[$SECS-1]
done
echo "Time is up, clown."

来源：https://stackoverflow.com/questions/21424985/linux-bash-timer