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★ Cron cheat sheet

Cron Expression: Every Friday at 5pm

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The expression

0 17 * * 5

At 17:00 on Friday.

  1. 0Minute
  2. 17Hour
  3. *Day of month
  4. *Month
  5. 5Day of week

✓ Valid 5-field cron

Quick picks

Typing by hand. Pick a pattern above to build one with inputs instead.

In plain English

At 17:00 on Friday.

Next 10 runs

Paste it into your platform

Time zone: UTC

0 17 * * 5 /usr/local/bin/my-job >> /var/log/my-job.log 2>&1
  • OKRuns in the server’s local time zone. cronie (RHEL, Fedora) accepts a CRON_TZ= line above the job; Debian’s cron does not.
  • Heads-upEscape % as \% in the command: an unescaped % ends the command and starts stdin.
  • Heads-upcron runs with a minimal PATH and no login shell. Use absolute paths and redirect output, or failures disappear.
  • Linux crontab docs ↗

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01

What 0 17 * * 5 means

Field by field:

Field breakdown
FieldValueMatches
Minute00
Hour1717
Day of month*any
Month*any
Day of week5Friday
02

Gotchas

  • 17 is 5pm on the 24-hour clock. 5 in the hour field would be 5am.
  • On AWS EventBridge Friday is 6, not 5.
03

Does it run everywhere?

Checked against each platform's rules, assuming UTC:

Platform support
PlatformVerdictWhy
Linux crontabWorks, with a catchEscape % as \% in the command: an unescaped % ends the command and starts stdin.
GitHub ActionsWorks, with a catchRuns at minute 0 are the most likely to be delayed or dropped under load. GitHub suggests another minute, e.g. 17.
VercelWorks, with a catchVercel now labels Cron Jobs “legacy” in favour of Vercel Schedules, which add time zones. Existing crons keep working.
AWS EventBridgeWorksSix fields: the year is added at the end, and one of day-of-month / day-of-week must be ?.
KubernetesWorks, with a catchWithout timeZone, the schedule uses the kube-controller-manager’s local zone. TZ= or CRON_TZ= inside schedule is rejected from v1.29.
04

Questions engineers actually ask

What is the cron for Friday at 5pm?
0 17 * * 5, or 0 17 * * FRI.
How do I run on the last Friday of the month?
Standard cron can’t. Run every Friday and exit unless next Friday is in a new month. AWS EventBridge supports 6L directly.
Why does my job run on days I didn't expect?
Probably the day-of-month / day-of-week OR rule. If both fields are set, cron runs when either matches. Set one of them to * to get the usual AND behaviour.
What time zone does cron use?
Whatever the scheduler uses: the server's zone for Linux cron, UTC for Vercel and EventBridge rules, UTC by default on GitHub Actions (with an optional timezone key) and the controller's zone on Kubernetes unless spec.timeZone is set.
05

Other schedules

06

More from the workbench

Fine print

Tools: on the house.
Engineer: by the hour.

Infra that doesn't page you at 3am costs a little more. I build background job systems with retries, alerting and dashboards.

I'm Himanshu, an AI and full-stack engineer. I build MVPs, AI agents and the growth plumbing around them for early-stage startups.