Cron use cases
These jobs all fail silently when they stop. Each guide gives you a cron expression, a worked crontab line, the ways that job fails, and how to tell when a run never happened. It also says when cron is the wrong tool.
Scheduling database backups with cron
Nightly pg_dump/mysqldump with locking, retention, and a way to notice when it stops working.
Scheduling log rotation, and why you probably shouldn't use cron
Almost always logrotate's job, already wired into cron.daily. Here's when to write your own.
Scheduling TLS certificate renewal
Certbot and acme.sh already schedule themselves. Here's what's left for you to own.
Scheduling cache warming with cron
Pre-hit expensive or cold paths on a schedule so real users never pay the first-request cost.
Scheduling recurring report generation
Weekly or monthly report jobs, and the date-math bugs that make them wrong on specific days.
Scheduling data sync and ETL jobs with cron
Incremental sync/ETL runs with locking and idempotency, and where cron alone stops being enough.
Scheduling temp file and cache directory cleanup
Age-based deletion of stale temp/cache files, and why /tmp itself is probably already handled.
Scheduling health checks with cron
Cron's one-minute floor is too coarse for most health checks. Here's what to use instead, and when cron is fine.
Scheduling email digests with cron
Daily or weekly digest sends, timezone-aware, with delivery failures treated as separate from generation.
Scheduling disk space monitoring with cron
A simple threshold check for one host, and where it stops scaling once you have a fleet.
Scheduling dependency and security scans with cron
Periodic scans of what's actually deployed. They back up CI-time scanning and don't replace it.