Cron Expression for Every 6 Hours
0 */6 * * *0 */6 * * * runs four times a day at 00:00, 06:00, 12:00 and 18:00. Six divides 24 evenly, so the schedule is perfectly regular across days.
Next runs, in your timezone
Four runs, fixed times
*/6 in the hour field expands to 0,6,12,18. Because the step divides 24 exactly, the gap is always six hours, including across midnight — which is not true for steps like 5 or 7.
0 */6 * * * /path/to/job.sh >> /var/log/myjob.log 2>&1Shifting the phase
If 00:00 lands in a backup window, offset the whole set: 0 3-21/6 fires at 03:00, 09:00, 15:00, 21:00 — still every six hours.
Equivalent expressions
0 0,6,12,18 * * *— explicit list — identical schedule0 3-21/6 * * *— same cadence shifted three hours
Run a SQL query on this schedule
If the job behind this schedule is a database query, you can skip the server and the crontab: SaturnSQL runs saved SQL queries on a cron expression — this exact syntax, with a real timezone field — and delivers the results to Google Sheets or Slack. Minimum interval 5 minutes.