CentOS timed Execution Script configuration

Service Crond start/starting Services
Service Crond stop//off services
Service Crond restart//Restart services
Service Crond Reload//Once again load configuration
There are two ways to add new scheduling tasks:
1, at the command line input: CRONTAB-E and then add the corresponding task, WQ disk exit.
2), directly edit/etc/crontab file. That is Vi/etc/crontab, add the corresponding task.

The CRONTAB-E configuration is for a user. and editing/etc/crontab is a task for the system
View Scheduled Tasks
Crontab-l//List of all current scheduled tasks
Crontab-l-u JP//List all scheduled tasks for user JP
Delete Task scheduling work
Crontab-r//Delete all task scheduling work
Direct edit Vim/etc/crontab, default file form such as the following