A cron job is a scheduled task that runs automatically on a Unix-like system at specified times or intervals. It relies on the cron daemon, which checks a configuration file known as a crontab to determine which commands to execute and when. Cron jobs are commonly used for maintenance tasks such as database backups, log cleanup, report generation, or triggering recurring scripts. Because they run in the background without user interaction, cron jobs are essential for automating routine operations.
Why it matters
Cron jobs enable predictable automation, reduce manual workload, and ensure critical tasks happen on time. They are especially important for backend systems, where recurring maintenance must happen reliably even when no users are active. Many cloud environments and container orchestration platforms emulate or extend cron-like scheduling for distributed systems.
Examples
Running a nightly task to process analytics data or sending scheduled email digests are classic cron use cases. Cron concepts appear frequently in lessons about system services and background work, such as Background Jobs and Queues.