简介：设置Linux设备定时重启或者关机
问题：有台设备每天总需要使用的人手动重启一下才可以正常工作，但是检查了日志，看起来服务一切都正常。时间和正确时间相差4mins。
解决办法：
1.增加定时任务，设置自动重启；
2.修改正确时间，并增加自动同步；
都是相对比较简单的命令，这里简单记录一下，可以供需要的同学参考；
增加定时任务，设置自动重启：
编辑crontab：
sudo crontab -e
增加定时重启命令，查看crontab
lifeccp@raspberrypi:~ $ sudo crontab -l
# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use ‘*‘ in these fields (for ‘any‘).#
# Notice that tasks will be started based on the cron‘s system
# daemon‘s notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h dom mon dow command
0 10 * * * sudo -u root reboot
重启服务确保生效：
sudo service cron restart
sudo vi /etc/sudoers
其他：
需要root权限才能执行的crontab，比如shutdown关机 需要： sudo crontab -e
在编辑器中加入下面2行，先将时间记录到日志中，每天22点30分钟 执行关机命令，1分钟警告后会自动关机
30 22 * * * date >> /home/haochuang/temp/shutdown.log
30 22 * * * sudo -u root shutdown -h 1
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