Cron expression examples

Cron every 8 hours

The cron expression for every 8 hours is 0 */8 * * *. In words: on the hour, every 8 hours.

What each field means

FieldValueMeaning
Minute0minute 0
Hour*/8every 8 hours
Day of month*any day of the month
Month*every month
Day of week*any day of the week

Times are in the timezone of whatever runs the schedule: the server's local time for crontab, UTC for GitHub Actions.

Use it

In a crontab, with a FlatLyne ping after the job succeeds:

0 */8 * * * /usr/local/bin/job.sh && curl -fsS -m 10 --retry 5 https://api.flatlyne.com/<ping-token>

In a Kubernetes CronJob:

apiVersion: batch/v1
kind: CronJob
spec:
  schedule: "0 */8 * * *"
  timeZone: "Etc/UTC"

In a GitHub Actions workflow (always UTC):

on:
  schedule:
    - cron: "0 */8 * * *"

Know when it doesn't run

Cron doesn't tell you when a job fails or never starts. Create a FlatLyne check with the schedule 0 */8 * * *, add the curl above to your job, and get an email, Slack message or PagerDuty incident when a ping is late. See how to monitor a cron job.

Monitor this schedule

Related schedules

Have a different expression? Paste it into the cron expression tool, or browse all examples.