linux 倒计时

BROWNWANG-MB0:~ wangzi$ cat a.sh
#!/bin/bash
i=10
while [ $i -gt 0 ]
do
printf %30s"$i""\n"
       let i--
sleep 1
done
BROWNWANG-MB0:~ wangzi$ bash a.sh
                              10
                              9
                              8
                              7
                              6
                              5
                              4
                              3
                              2
                              1