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OpenSolaris 2009.06 - man page for cron (opensolaris section 1m)

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cron(1M)			  System Administration Commands			 cron(1M)

       cron - clock daemon


       cron starts a process that executes commands at specified dates and times.

       You  can  specify  regularly scheduled commands to cron according to instructions found in
       crontab files in the  directory	/var/spool/cron/crontabs.  Users  can  submit  their  own
       crontab file using the crontab(1) command. Commands which are to be executed only once can
       be submitted using the at(1) command.

       cron only examines crontab or at command files during its own process initialization phase
       and  when  the crontab or at command is run. This reduces the overhead of checking for new
       or changed files at regularly scheduled intervals.

       As cron never exits, it should be executed only once. This is done routinely by way of the
       svc:/system/cron:default service. The file /etc/cron.d/FIFO file is used as a lock file to
       prevent the execution of more than one instance of cron.

       cron captures the output of the job's stdout and stderr streams, and, if it is not  empty,
       mails  the  output to the user. If the job does not produce output, no mail is sent to the
       user. An exception is if the job is an at(1) job and the -m option was specified when  the
       job was submitted.

       cron  and at jobs are not executed if your account is locked. Jobs and processses execute.
       The shadow(4) file defines which accounts are not locked and will have their jobs and pro-
       cesses executed.

   Setting cron Jobs Across Timezones
       The  timezone  of the cron daemon sets the system-wide timezone for cron entries. This, in
       turn, is by set by default system-wide using  /etc/default/init.  The  timezone	for  cron
       entries can be overridden in a user's crontab file; see crontab(1).

       If  some  form of daylight savings or summer/winter time is in effect, then jobs scheduled
       during the switchover period could be executed once, twice, or not at all.

   Setting cron Defaults
       To keep a log of  all  actions  taken  by  cron,  you  must  specify  CRONLOG=YES  in  the
       /etc/default/cron  file. If you specify CRONLOG=NO, no logging is done. Keeping the log is
       a user configurable option since cron usually creates huge log files.

       You can specify the PATH for user cron jobs by using PATH= in /etc/default/cron.  You  can
       set the PATH for root cron jobs using SUPATH= in /etc/default/cron. Carefully consider the
       security implications of setting PATH and SUPATH.

       Example /etc/default/cron file:


       This example enables  logging  and  sets  the  default  PATH  used  by  non-root  jobs  to
       /usr/bin:/usr/ucb:. Root jobs continue to use /usr/sbin:/usr/bin.

       The cron log file is periodically rotated by logadm(1M).

       /etc/cron.d		Main cron directory

       /etc/cron.d/FIFO 	Lock file

       /etc/default/cron	cron default settings file

       /var/cron/log		cron history information

       /var/spool/cron		Spool area

       /etc/cron.d/queuedefs	Queue description file for at, batch, and cron

       /etc/logadm.conf 	Configuration file for logadm

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWcsu			   |

       svcs(1),  at(1),  crontab(1),  sh(1),  logadm(1M),  svcadm(1M),	queuedefs(4),  shadow(4),
       attributes(5), rbac(5), smf(5), smf_security(5)

       The cron service is managed by the service management facility, smf(5), under the  service


       Administrative  actions	on  this  service,  such  as  enabling,  disabling, or requesting
       restart, can be performed using svcadm(1M). The service's status can be queried using  the
       svcs(1)	command.  Most	administrative	actions  may  be  delegated  to  users	with  the
       solaris.smf.manage.cron authorization (see rbac(5) and smf_security(5)).

       A history of all actions taken  by  cron  is  stored  in  /var/cron/log	and  possibly  in

SunOS 5.11				    4 Feb 2009					 cron(1M)
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