linux下设置定时执行脚本

﹏ヽ暗。殇╰゛Y 2022-03-17 09:12 480阅读 0赞

### linux下设置定时执行脚本 ###

**1.首先安装所需程序并启动**  
**crontabs是设置周期性被执行的指令**

yum install vixie-cron
        yum install crontabs
        service crond start
        service crond stop
        service crond status

**出现以下信息则表示crond启动成功**

● crond.service - Command Scheduler
       Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
       Active: active (running) since Fri 2019-02-15 02:13:57 EST; 1 weeks 0 days ago
     Main PID: 94183 (crond)
        Tasks: 1
       Memory: 344.0K
       CGroup: /system.slice/crond.service
               └─94183 /usr/sbin/crond -n

**2.将crond加入开机启动**  
**就是把service crond start加入开机启动脚本  
开机启动脚本可以参考我的另一篇博客：[https://blog.csdn.net/qq\_41969358/article/details/87798908][https_blog.csdn.net_qq_41969358_article_details_87798908]**

**3.添加定时任务**  
`vi /etc/crontab`**，例如设置每天晚上12点重启服务器**  
**tip:定时任务失败很多时候都是crontab时间格式错误**

SHELL=/bin/bash
    PATH=/sbin:/bin:/usr/sbin:/usr/bin
    MAILTO=root
    
    # For details see man 4 crontabs
    
    # Example of job definition:
    # .---------------- minute (0 - 59)
    # |  .------------- hour (0 - 23)
    # |  |  .---------- day of month (1 - 31)
    # |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
    # |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
    # |  |  |  |  |
    # *  *  *  *  * user-name  command to be executed
      0 0  *  *  * root reboot

**4.添加完定时任务后，重启crond，使改动生效**

service crond restart

**5.查看是否生效**  
**实时查看crontab执行内容**

tail -f /var/log/cron

**通过系统日志来查看Cron任务是否有执行过**

grep "reboot" /var/log/cron

[https_blog.csdn.net_qq_41969358_article_details_87798908]: https://blog.csdn.net/qq_41969358/article/details/87798908