Cron is a time-based job scheduler found in Unix-like operating systems. A cron expression is a string of five fields separated by spaces, representing minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-6). Special characters like * (every), */N (every N), - (range), and , (list) allow complex scheduling patterns. Cron is used in Linux servers for automated backups, log rotation, report generation, database maintenance, and deployment pipelines. Kubernetes CronJobs, GitHub Actions, and CI/CD platforms all use cron syntax for scheduling.
0 * * * * runs at the start of every hour. 0 0 * * * runs at midnight daily. 0 0 * * 0 runs at midnight every Sunday. */5 * * * * runs every 5 minutes. 0 9-17 * * 1-5 runs every hour from 9 AM to 5 PM on weekdays. This tool helps you build these expressions visually and shows the next execution times so you can verify your schedule before deploying it.