17 articles
The exact Quartz.NET 3.22.9 cron rules from CronExpression.cs: why one day field must be ?, what L, W, LW, L-n, and # mean, what the builder helpers return, how daylight saving moves a run, and how to rewrite a Quartz string as a five-field UTC schedule.
Anacron runs daily, weekly, and monthly jobs once per period, even on machines that were switched off. When each distribution starts it, the anacrontab format, and why cron.daily skipped today.
Spring-forward skips an hour and fall-back repeats one. Which schedulers skip, delay, or double a job on those nights, checked against their source, and how to keep local-time jobs safe.
Cron works in whole minutes. Five ways to run work every 30 seconds, what each one does when a run overruns its slot, when a queue consumer beats a schedule, and how to monitor it per minute.
Debian, Fedora, Alpine, and containers each run a different cron. Identify yours with two commands and see how they differ on variables, CRON_TZ, day fields, DST, percent signs, and output.
Five-field cron cannot say "last day of the month." The 28-31 date test, BSD and BusyBox variants, last weekday and first Monday, Quartz and systemd syntax, and how to monitor it.
A job that never starts produces no error, no log line, and no failed health check. Seven scheduled-job failures mapped to the tool that sees each one, and how to combine them.
@reboot runs when the cron daemon starts, not when the system is ready. What cronie, Debian cron, and BusyBox actually do, why boot jobs fail, and when a systemd unit is the better tool.
Which time zone cron uses, why TZ= in a crontab never moves the schedule, where CRON_TZ works, the tzdata traps in containers, and how to diagnose a job that runs hours off.
crontab -r deletes without asking, and crontab file replaces everything. Edit, back up, and restore crontabs safely, and find every cron job on a Linux server.
Exact Hangfire 1.8 cron syntax, what each Cron helper returns, how RecurringJobOptions.TimeZone resolves on Windows and Linux, and what happens when daylight saving skips or repeats an hour.
Cron began in 1975 as a Bell Labs daemon reading one table every minute. How System V, BSD, Paul Vixie, POSIX, Linux, systemd, and Kubernetes shaped the cron you run today.
Cron skips it, anacron and persistent timers run it once, Kubernetes creates one Job, and strict misfire modes replay every run. Catch-up after downtime, checked against source code.
A batch job that isn't running has nothing to scrape. How pull, push, and the hybrids between them detect missed, failed, and stuck runs, where each one goes blind, and which to use.
SmartPolicy, FireOnceNow, DoNothing, and IgnoreMisfirePolicy traced through the Quartz.NET 3.x source: the real misfireThreshold default, when misfires are detected, and a downtime timeline.
Cron wakes every minute, runs each matching crontab line through the shell, and mails any output. Which cron each distro ships, what it leaves to you, and why its classic failure is silence.
A practical cron expression reference: the five fields, operators, a table of common schedules, every-2-months jobs, and the mistakes that make cron run at the wrong time.