Cron Explainer.

It runs once a day at 02:00: minute 0, hour 2, every day-of-month, every month, every day-of-week. That is the expression loaded in the box above. It is also the worst hour to pick on a server that observes daylight saving, because 02:00 local is exactly the time that gets skipped or repeated twice a year.

Almost always the day-of-month versus day-of-week trap. When both of those fields are restricted, cron runs the job if either one matches, not both, so 0 0 13 * 5 fires on the 13th of every month and on every Friday, roughly sixty times a year, instead of on Friday the 13th. Leave one of the two fields as * and the usual AND behaviour comes back.

No. A step expands to a set within the field, so */7 means minutes 0, 7, 14, 21, 28, 35, 42, 49 and 56, and then the hour rolls over and the count restarts at zero. The last gap is four minutes, not seven. Steps only give an even interval when they divide the field evenly. For minutes that means 2, 3, 4, 5, 6, 10, 12, 15, 20 or 30.

Whatever timezone the scheduler itself is in, which is usually the system timezone rather than UTC. cronie and Debian's cron let you put a CRON_TZ=Europe/Paris line at the top of a crontab, Kubernetes CronJob takes spec.timeZone, and most application schedulers simply inherit the process timezone. Running schedulers in UTC and converting only for display removes a whole class of daylight-saving bugs.

Environment. Cron hands a job a nearly empty environment with a minimal PATH (often just /usr/bin:/bin) no shell profile, and none of the variables your interactive login sets, so a command that resolves fine for you comes back 'not found'. Use absolute paths for every binary, and remember that % is special inside a crontab command: it is turned into a newline unless you escape it as \%, which is why date +%Y silently breaks.

It reads the standard five-field crontab format: *, single values, ranges, comma lists, steps, and month and weekday names like JAN and MON. The Vixie shortcuts @yearly, @annually, @monthly, @weekly, @daily, @midnight and @hourly are expanded to their five-field form, and @reboot is explained but has no next run time. Six-field seconds-first expressions and Quartz tokens such as ? L W and # are rejected rather than guessed at. Everything is parsed in your browser as you type, and the expression is never sent anywhere.

The Laravel box under the next run times turns the expression into the closest fluent method, such as ->dailyAt('2:00'), ->everyFifteenMinutes() or ->weeklyOn(Schedule::MONDAY, '9:00'), and falls back to ->cron('...') when no helper fits. Put the line in routes/console.php, swap in your own command name, and keep a single system cron entry that runs php artisan schedule:run every minute. Laravel uses the app timezone unless you add ->timezone().

The page walks forward minute by minute from now and lists the first five matches, in your browser's time zone or in UTC. It follows Vixie rules, so when both day fields are restricted a day matches if either one does. Times that do not exist because of a daylight saving jump are skipped, the same way most cron daemons skip them.