Cron: Every 8 Hours
0 */8 * * * fires three times a day — midnight, 8 AM, and 4 PM — evenly dividing the day into thirds. It naturally lines up with classic 8-hour shift patterns, making it a familiar cadence for operations and monitoring tasks tied to shift handoffs.
0 */8 * * *
Examples & Variations
Common Mistakes
- Assuming the three run times automatically align with your team's actual shift schedule — the step form starts at midnight; use an explicit list (like 6,14,22) if shifts start at a different hour.
- Treating three-times-daily as 'infrequent enough to skip monitoring' — a missed run here represents a third of the day's coverage, larger than it sounds.
- Running resource-intensive jobs at all three slots without considering that one of them always lands overnight, potentially colliding with other nightly maintenance.
Best Practices
- If this schedule is meant to mirror real shift handoffs, use the explicit hour list rather than the step syntax so the crontab entry documents the actual shift start times.
- A reasonable default for reports or sync jobs that need same-day freshness without hourly overhead.
- Restrict to weekdays if the job supports a Monday–Friday operation and shouldn't run on weekend shifts.
Frequently Asked Questions
- What three times does every 8 hours run?
- Midnight, 8 AM, and 4 PM by default — an even three-way split of the 24-hour day starting from hour 0.
- How do I align every-8-hours with a 7 AM shift start instead?
- Use an explicit list: 0 7,15,23 * * * keeps the 8-hour spacing but starts at 7 AM instead of midnight.
- Is 0 */8 * * * the same as 0 0,8,16 * * *?
- Yes, exactly equivalent — the step form is shorthand for that explicit list.