Centos 7 crontab

Crontab reads the/etc/crontab file and/etc/cron every minute by default. d/directory and/var/spool/cron/directory once. The format of the three tasks is consistent, only the tasks in the/var/spool/cron/directory need to be created using the crontab-e command. Different users will be created in the/var/spool/cron/user name file. However, the task configuration file is stored in the cron. d directory, not the executable file. Commands are generally used to create user tasks, and the other two are system tasks.

Centos 7 is in cron by default. 0 hourly is placed in the d directory, and the subject content is: 01 ***** root run-parts/etc/cron. hourly task to start anacron, and use anacron to check/etc/cron. daily,/etc/cron. weekly,/etc/cron. monthly directories (anacron cannot define tasks with a frequency of less than one day), instead of using the crontab configuration file in most versions to start the tasks of these three directories.

Cron is in the form of system service crond and in the system. It can be managed through/sbin/service, and Anacron is a general program.