Linux
Beginner
What is Crontab Syntax?
The time specification format used in cron job scheduling, with five fields defining minute, hour, day of month, month, and day of week.
Crontab uses five space-separated fields: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-7, where 0 and 7 are Sunday). Special characters include * (any value), , (list: 1,3,5), - (range: 1-5), / (step: */5 means every 5). Common patterns: "0 * * * *" (hourly), "0 0 * * *" (daily midnight), "0 0 * * 0" (weekly Sunday), "0 0 1 * *" (monthly), "*/15 * * * *" (every 15 minutes). Edit with crontab -e, list with crontab -l. System crontab (/etc/crontab) includes a username field. The @reboot, @daily, @weekly shortcuts simplify common schedules.
