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 crond service, which is a
symlink to the actual service (e.g. dcron). If you install several
implementations, you can choose which one to use via
xbps-alternatives(1); this will
alter the crond symlink appropriately. Implementation documentation will be
available in crond(8).
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.