About CronProbe
What this is
Cron tools that run in your browser. Nothing you type is uploaded.
| Tool | What it does |
|---|---|
| Expression checker (home page) | Parses five fields, shows what each expands to, writes the schedule in plain English, and lists the next eight runs in your browser's time zone. Accepts @yearly, @monthly, @weekly, @daily, @hourly and @reboot. |
| Crontab checker | Checks a whole crontab: invalid schedules, environment lines, an unescaped % in a command, commands with no path, an empty MAILTO, and the day-of-month/day-of-week OR rule. |
| Time-zone runs | Next runs on the wall clock of any IANA zone next to UTC, and the scheduled times a daylight-saving gap removes. |
Rules it applies
- Vixie semantics: when both day-of-month and day-of-week are restricted the schedule fires when either matches. Day-of-week 7 is Sunday. Steps, ranges and lists work as in
crontab(5). - A sixth leading field (seconds, Quartz style) is rejected, because standard cron has five.
- Names (
JAN,MON) andL,W,#,?are not accepted: they are not part of the five-field format everywhere, so the checker refuses them instead of guessing.
Where the answer depends on your system
The next-run list uses the browser's time zone unless you pick one on the time-zone page. Your server's cron daemon uses the server's zone, or CRON_TZ where the daemon supports it. A run list is only as right as that match. Some daemons also differ in how they handle the repeated hour when clocks go back.