Crontab is a file containing instructions for the cron daemon. It is a job scheduler where you add commands to be executed at defined periods.
Edit existing crontab file, or make new one if it doesn’t exist:
crontab -eList of cronjobs , display crontab file contents:
crontab -lReload crontab:
service cron reload(not necessary since the system will check periodically for crontab changes and apply them)
Removes the crontab file:
crontab -rTime format in crontab
| * | * | * | * | * | command |
| min (0-59) | hour (0-23) | day of the month (1-31) | month (1-12) | day of the week (0-6) | |
| Sunday = 0 |
* is a wildcard, meaning any value from the given range
/ adds a step value
*/5 * * * *This will be executed every 5 minutes.
0 18 * * 1-3This will be executed at 18:00h on every day of the week from Monday to Wednesday.