Another form allows the user to specify an exact time or a delay before shutdown: shutdown -h 20:00 will turn the computer off at 8:00 PM, and shutdown -r -t 60 will automatically reboot the machine within 60 seconds (one minute) of issuing the command.
还有一种常见用法能让用户指定确切关机时间或延迟关机时间：shutdown -h 20:00会让计算机在8:00PM关机，shutdown -r -t 60会让计算机在这条命令执行的60秒（一分钟）后重启。