/etc/crontab

# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when you edit this file
# and files in /etc/cron.d. These files also have username fields,
# that none of the other crontabs do.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# m h dom mon dow user	command
17 *	* * *	root    cd / && run-parts --report /etc/cron.hourly
25 6	* * *	root	test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
47 6	* * 7	root	test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
52 6	1 * *	root	test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
#

crontab -e

See also

• Test mode: nginx -t, sshd -T, crontab -e, visudo, Named-checkconf, dnsmasq --test, validate:
• cron, crontab, systemctl list-timers, anacron, Kubernetes scheduler, Systemd services, CronJobsStack, cron.schedule, crontab -l, 0x004b, at, /etc/cron.deny, /etc/cron.allow, /etc/crontab, /var/spool/cron/crontabs/