crond task scheduling:
It refers to the system to perform a specific command or application at a time.
Category: 1, the system work, and some important work must be performed again and again, such as virus scanning; 2, individual users work, individual users may wish to perform certain procedures, such as mysql database backup
The basic syntax:
crontab [options]
[-E] cron job edit crontab
[-L] Query task crontab
[-R] to delete the current user's crontab all tasks
Case: / etc / crontab
* / 1 * * * * ls -l / etc >> /tmp/to.txt: do not add content to to.txt in minutes
Parameter details Description:
* For any time, such as the first representative of a * hours a once per minute
Representative discontinuous time, such as "0 8,12,16 * * *" represents the day 8:00, 12:00, 16:00 execute a command
- represents the continuous time range, such as "* 1-6 * 05" represents Monday to Saturday 5:00 Run
* / N representative of how often executed once. As represented in the example described above is performed once every minute command
Task set by the script file:
1, writing shell scripts, such as vim /home/mytask.sh
date >> /tmp/mydate
2, an executable permission to mytask.sh
chmod 744 /home/mytask.sh
3、crontab -e
*/1 * * * * /home/mytask.sh
Restart task scheduling:
service crond start