NAME

cron − clock daemon

SYNOPSIS

/etc/cron

DESCRIPTION

Cron executes commands at specified dates and times.  Regularly scheduled commands can be specified according to instructions found in crontab files; users can submit their own crontab file via the crontab(1M) command. Commands which are to be executed only once may be submitted via the at command.  Since cron never exits, it should only be executed once.  This is best done by running cron from the initialization process through the file /etc/rc (see init(1M)). 

Cron only examines crontab files and at(1) command files during process initialization and when a file changes. This reduces the overhead of checking for new or changed files at regularly scheduled intervals.

DIAGNOSTICS

A history of all actions taken by cron is recorded in /usr/lib/cron/log. 

DEPENDENCIES

Series 300 Diskless
The directories /usr/lib/cron and /usr/spool/cron are context dependent files (CDFs) in a clustered environment.  Each cnode is expected to run its own copy of cron. 

AUTHOR

Cron was developed by AT&T and HP. 

FILES

SEE ALSO

at(1), crontab(1), init(1M), sh(1). 

Hewlett-Packard Company  —  Version B.1,  May 11, 2021