Reference https://www.cnblogs.com/xd502djj/p/3612131.html
In some shell (such as bash linux in) in sleep also supports sleep (minutes, hours)
sleep 1 睡眠1秒
sleep 1s 睡眠1秒
sleep 1m 睡眠1分
sleep 1h 睡眠1小时
Reproduced in: https: //www.jianshu.com/p/9dacb545745a