Cron Job

Cron jobs automate repetitive tasks like backups, reports, and maintenance.

Components

• Cron expression: Defines when to run (minute, hour, day, month, weekday).
• Command/script: What to execute.
• User context: Which user runs the job.
• Output: Where logs/errors go (email, file).

Common uses

• Database backups (daily at midnight).
• Log rotation (weekly cleanup).
• Report generation (monthly summaries).
• Health checks (every 5 minutes).
• Certificate renewal (automated Let's Encrypt).

Best practices

• Log all job output for debugging.
• Use absolute paths in scripts.
• Set appropriate timeouts.
• Handle failures gracefully.
• Test in non-production first.
• Document what each job does.

Alternatives

• Systemd timers (Linux).
• Task Scheduler (Windows).
• Cloud schedulers (AWS EventBridge, Cloud Scheduler).