cron is a daemon for running programs at regular intervals. The programs and intervals are specified in a crontab file, which can be edited with crontab(1). Running crontab -e as the superuser will edit the system crontab; otherwise, it will edit the crontab for the current user.

By default, a cron daemon is not installed. However, multiple cron implementations are available, including cronie, dcron, fcron and more.

Once you have chosen and installed an implementation, enable the corresponding service. There is also a generic crond service which is maintained by the alternatives system, but there is no real benefit in using it and just makes your setup harder to follow.

As an alternative to the standard cron implementations, you can use snooze(1) together with the snooze-hourly, snooze-daily, snooze-weekly and snooze-monthly services, which are provided by the snooze package for this purpose. Each of these services execute scripts in the respective /etc/cron.* directories.