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CRON(8)             UNIX Programmer's Manual		  CRON(8)



[1mNAME
     [0mcron - clock daemon

[1mSYNOPSIS
     /usr/sbin/cron

DESCRIPTION
     Cron [0mexecutes commands at specified dates and times accord-
     ing to instructions in the files stored in
     [1m/var/spool/cron/crontabs [0mand [1m/var/spool/cron/atjobs.
     [0mA user can create a crontab file using the [1mcrontab(1) [0mcom-
     mand. A command which only needs to be executed once can be
     submitted using [1mat(1) [0mor [1mbatch(1). [0mCron only updates its
     queues of jobs to be run when it starts up and when one of
     the job files is created or removed using [1mat, batch [0mor [1mcron-
     tab. [0mSince [1mcron [0mnever exits, it should only be executed
     once.  This is best done by running [1mcron [0mfrom the initiali-
     zation process through the file /etc/rc; see [1minit(8).

     cron [0mcommunicates with [1mcrontab [0mand [1mat [0musing a FIFO,
     [1m/var/spool/cron/crontabs/FIFO. [0mThis file is also used to
     make sure that only one instance of cron is running on a
     system, i.e. cron will fail if it finds that this file
     already exists.

[1mFILES
     [0m/var/spool/cron/FIFO	  FIFO used by cron, crontab and at
     /var/spool/cron/queuedefs	  queue description file
     /var/spool/cron/.proto	  used by at(1) for creating job files
     /var/spool/cron/crontabs	  directory containing crontab files
     /var/spool/cron/atjobs	  directory containing atjob files

[1mDIAGNOSTICS
     [0mError messages are handled by syslogd (facility name
     `cron').

[1mSEE ALSO
     [0mat(1), crontab(1), init(8), syslogd(8)

















Printed 4/12/91     Revision 1.6 of 17/09/90			1



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