crond

crond [OPTIONS]

crond is a daemon that executes scheduled commands from crontab files. It starts automatically at boot and checks crontab files for jobs that need to run each minute. It monitors /var/spool/cron/ (user crontabs), /etc/crontab (system crontab), and /etc/cron.d/ (system cronjobs). The flags below describe the cronie implementation, the crond shipped on most modern distributions; BusyBox and dcron provide their own crond with overlapping but not identical options.

-n

Run in foreground (useful for init systems)

Send job output to syslog instead of email

Specify custom mail command or disable with "off"

Override default limitations and accept custom crontabs

Inherit PATH from environment instead of setting default

Enable clustering support for shared crontabs

Display help information

Display version number

/etc/crontab

System-wide crontab file monitored by crond.

Directory containing additional system crontab files.

Directory containing user-specific crontab files (one per user). Debian's cron uses /var/spool/cron/crontabs/ instead.

Job output is mailed to the crontab owner unless redirected to syslog with -s or a custom mail command. Crontab files must be regular files, not executable, and writable only by the owner. Local time changes (like DST) under three hours receive special handling.

crond is the daemon component of cron, a standard Unix job scheduler that has been in use since Version 7 Unix. Modern implementations include Vixie cron and cronie.

crontab(1), crontab(5), anacron(8)

Source code