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

6       cron - clock daemon
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SYNOPSIS

9       /usr/sbin/cron
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DESCRIPTION

13       cron  starts  a  process  that executes commands at specified dates and
14       times.
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17       You can specify regularly  scheduled  commands  to  cron  according  to
18       instructions    found    in    crontab    files    in   the   directory
19       /var/spool/cron/crontabs. Users can submit their own crontab file using
20       the crontab(1) command. Commands which are to be executed only once can
21       be submitted using the at(1) command.
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24       cron only examines crontab or at command files during its  own  process
25       initialization  phase  and  when the crontab or at command is run. This
26       reduces the overhead of checking for new or changed files at  regularly
27       scheduled intervals.
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30       As cron never exits, it should be executed only once. This is done rou‐
31       tinely  by  way  of  the  svc:/system/cron:default  service.  The  file
32       /etc/cron.d/FIFO  file  is used as a lock file to prevent the execution
33       of more than one instance of cron.
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36       cron captures the output of the job's stdout and stderr  streams,  and,
37       if  it  is not empty, mails the output to the user. If the job does not
38       produce output, no mail is sent to the user. An exception is if the job
39       is  an  at(1) job and the -m option was specified when the job was sub‐
40       mitted.
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43       cron and at jobs are not executed if your account is locked.  Jobs  and
44       processses  execute.  The shadow(4) file defines which accounts are not
45       locked and will have their jobs and processes executed.
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47   Setting cron Jobs Across Timezones
48       The timezone of the cron daemon sets the system-wide timezone for  cron
49       entries.  This,  in  turn,  is  by  set  by  default  system-wide using
50       /etc/default/init. The timezone for cron entries can be overridden in a
51       user's crontab file; see crontab(1).
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54       If  some  form  of daylight savings or summer/winter time is in effect,
55       then jobs scheduled during the  switchover  period  could  be  executed
56       once, twice, or not at all.
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58   Setting cron Defaults
59       To  keep  a  log  of  all actions taken by cron, you must specify CRON‐
60       LOG=YES in the /etc/default/cron file. If you  specify  CRONLOG=NO,  no
61       logging  is  done.  Keeping the log is a user configurable option since
62       cron usually creates huge log files.
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65       You can specify  the  PATH  for  user  cron  jobs  by  using  PATH=  in
66       /etc/default/cron.  You  can  set  the  PATH  for  root cron jobs using
67       SUPATH= in /etc/default/cron. Carefully consider the security  implica‐
68       tions of setting PATH and SUPATH.
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70
71       Example /etc/default/cron file:
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73         CRONLOG=YES
74         PATH=/usr/bin:/usr/ucb:
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79       This example enables logging and sets the default PATH used by non-root
80       jobs   to   /usr/bin:/usr/ucb:.   Root    jobs    continue    to    use
81       /usr/sbin:/usr/bin.
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84       The cron log file is periodically rotated by logadm(1M).
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FILES

87       /etc/cron.d              Main cron directory
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90       /etc/cron.d/FIFO         Lock file
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93       /etc/default/cron        cron default settings file
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96       /var/cron/log            cron history information
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99       /var/spool/cron          Spool area
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102       /etc/cron.d/queuedefs    Queue description file for at, batch, and cron
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105       /etc/logadm.conf         Configuration file for logadm
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ATTRIBUTES

109       See attributes(5) for descriptions of the following attributes:
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114       ┌─────────────────────────────┬─────────────────────────────┐
115       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
116       ├─────────────────────────────┼─────────────────────────────┤
117       │Availability                 │SUNWcsu                      │
118       └─────────────────────────────┴─────────────────────────────┘
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SEE ALSO

121       svcs(1),    at(1),    crontab(1),    sh(1),   logadm(1M),   svcadm(1M),
122       queuedefs(4),  shadow(4),  attributes(5),  rbac(5),  smf(5),  smf_secu‐
123       rity(5)
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NOTES

126       The cron service is managed by the service management facility, smf(5),
127       under the service identifier:
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129         svc:/system/cron:default
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134       Administrative actions on this service, such as enabling, disabling, or
135       requesting  restart,  can  be performed using svcadm(1M). The service's
136       status can be queried using the svcs(1)  command.  Most  administrative
137       actions  may  be  delegated  to  users with the solaris.smf.manage.cron
138       authorization (see rbac(5) and smf_security(5)).
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DIAGNOSTICS

141       A history of all actions taken by cron is stored in  /var/cron/log  and
142       possibly in /var/cron/olog.
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146SunOS 5.11                        4 Feb 2009                          cron(1M)
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