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Tools/Cron

crontab cron

The original crontab is five fields followed by a command. Most SaaS cron clones copied this layout. Day-of-month and day-of-week are OR'd if both are restricted — a common surprise.

Field format

minute hour day-of-month month day-of-week command

Open the builder

Gotchas

Does crontab use my local timezone?
It uses the system timezone of the host (or CRON_TZ on some implementations). Containers often run UTC.
What happens if I set both day-of-month and day-of-week?
Vixie cron runs the job when either matches. 0 0 1 * 1 is the 1st of the month or every Monday, not Mondays that fall on the 1st.

Examples

Snippet for crontab

GitHub Actions

UTC only. Quote the expression so YAML keeps the stars.

on:
  schedule:
    - cron: '0 9 * * 1'

Kubernetes

CronJob spec.schedule. Kubernetes uses the timezone of the kube-controller-manager unless you set .spec.timeZone.

apiVersion: batch/v1
kind: CronJob
metadata:
  name: job
spec:
  schedule: "0 9 * * 1"
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
            - name: job
              image: busybox
              args: ["echo", "run"]

AWS EventBridge

Six fields: minutes hours day-of-month month day-of-week year. Use ? in either day-of-month or day-of-week.

cron(0 9 ? * 1 *)

Quartz

Quartz is seconds-first (6 or 7 fields). Day-of-week names are MON, TUE, … and ? is required in one of the day fields.

0 0 9 * * 1

Vercel Cron

{
  "crons": [
    {
      "path": "/api/cron",
      "schedule": "0 9 * * 1"
    }
  ]
}

crontab

0 9 * * 1 /usr/local/bin/job

node-cron

import cron from 'node-cron';

cron.schedule('0 9 * * 1', () => {
  // job
});

Spring @Scheduled

Spring uses 6 fields by default (seconds first) unless you set spring.task.scheduling.cron.expression.

@Scheduled(cron = "0 0 9 * * 1")
public void run() {
    // job
}

Useful schedules

Other platforms