Crond task scheduling:
It means that the system executes a specific command or program at a certain time.
Classification: 1. System work, some important work must be performed repeatedly, such as virus scanning; 2. Individual user work, individual user may wish to execute some programs, such as MySQL database backup.
[-e] Editing Crontab Timing Tasks
[-l] Query Crontab Tasks
[-r] Delete all crontab tasks for the current user
Case: / etc/crontab
*/ 1 * * * * ls – L / etc > / TMP / to. txt: No minutes to add content to. TXT
Details of parameters:
* Represents that at any time, for example, the first * represents the total execution of an hour every minute.
Represents a discontinuous time, such as “0 8,12,16* *” means that an order is executed at 8:0, 12:0 and 16:0 every day.
– Represents a continuous time range, such as “0.5* * 1-6” implements orders from Monday to Saturday at 5:0 a.m.
*/ n stands for how often it is executed. As in the example above, the command is executed every minute on behalf of the representative.
Setting tasks through file scripts:
1. Write shell scripts, such as vim/home/mytask.sh
date >> /tmp/mydate
2. Give mytask.sh an executable privilege
chmod 744 /home/mytask.sh
*/1 * * * * /home/mytask.sh
Restart task scheduling:
service crond start