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crontab(1)

crontab(1)                       User Commands                      crontab(1)

NAME
       crontab - user crontab file

SYNOPSIS
       /usr/bin/crontab [filename]


       /usr/bin/crontab -e [username]


       /usr/bin/crontab -l [username]


       /usr/bin/crontab -r [username]


       /usr/xpg4/bin/crontab [filename]


       /usr/xpg4/bin/crontab -e [username]


       /usr/xpg4/bin/crontab -l [username]


       /usr/xpg4/bin/crontab -r [username]


       /usr/xpg6/bin/crontab [filename]


       /usr/xpg6/bin/crontab -e [username]


       /usr/xpg6/bin/crontab -l [username]


       /usr/xpg6/bin/crontab -r [username]

DESCRIPTION
       The  crontab utility manages a user's access with cron (see cron(8)) by
       copying, creating, listing, and  removing  crontab  files.  If  invoked
       without options, crontab copies the specified file, or the standard in‐
       put  if  no  file  is specified, into a directory that holds all users'
       crontabs.


       If crontab is  invoked  with  filename,  this  overwrites  an  existing
       crontab entry for the user that invokes it.

   crontab Access Control
       Users: Access to crontab is allowed:

           o      if the user's name appears in /etc/cron.d/cron.allow.


           o      if /etc/cron.d/cron.allow does not exist and the user's name
                  is not in /etc/cron.d/cron.deny.



       Users: Access to crontab is denied:

           o      if  /etc/cron.d/cron.allow exists and the user's name is not
                  in it.


           o      if /etc/cron.d/cron.allow does not exist and user's name  is
                  in /etc/cron.d/cron.deny.


           o      if   neither   file   exists,  only  a  user  with  the  so‐
                  laris.jobs.user authorization is allowed to submit a job.


           o      if Solaris Auditing is enabled, the user's shell is not  au‐
                  dited  and the user is not the crontab owner. This can occur
                  if the user logs in by way of a program, such as  some  ver‐
                  sions of SSH, which does not set audit parameters.



       The rules for allow and deny apply to root only if the allow/deny files
       exist.


       The allow/deny files consist of one user name per line.

   crontab Entry Format
       A  crontab  file  consists  of lines of six fields each. The fields are
       separated by spaces or tabs. The first five are integer  patterns  that
       specify the following:

         minute (0−59),
         hour (0−23),
         day of the month (1−31),
         month of the year (1−12),
         day of the week (0−6 with 0=Sunday).



       Each  of  these  patterns  can be either an asterisk (meaning all legal
       values) or a list of elements separated by commas. An element is either
       a number or two numbers separated by a minus sign (meaning an inclusive
       range). Time specified here is interpreted in the currently active time
       zone. At the top of the crontab file this is the time zone which is set
       systemwide as described under TZ in the environ(7) manual page. A  user
       can add a line such as:

         TZ=timezone



       ...and all subsequent entries will be interpreted using that time zone,
       until  a new TZ=timezone line is encountered. The specification of days
       can be made by two fields (day of the month and day of the week).  Both
       are adhered to if specified as a list of elements. See EXAMPLES.


       The  sixth  field  of a line in a crontab file is a string that is exe‐
       cuted by the shell at the specified times. A percent character in  this
       field (unless escaped by \) is translated to a NEWLINE character.


       Only  the  first line (up to a '%' or end of line) of the command field
       is executed by the shell. Other lines are made available to the command
       as standard input. Any blank line or line beginning with  a  '#'  is  a
       comment and is ignored.


       The  shell  is  invoked  from  your  $HOME directory. As with $TZ, both
       $SHELL and $HOME can be set by having a line such as:

         SHELL=/usr/bin/someshell



       ...or:

         HOME=somedirectory



       ...which will take precedence for all  the  remaining  entries  in  the
       crontab  or  until  there is another HOME or SHELL entry. It is invoked
       with an arg0 of the basename of the $SHELL that is currently in effect.
       A user who wants to have their .profile  or  equivalent  file  executed
       must  explicitly do so in the crontab file. cron supplies a default en‐
       vironment for every shell, defining HOME, LOGNAME, SHELL, TZ, and PATH.
       The default PATH for user cron jobs is /usr/bin; while root  cron  jobs
       default  to /usr/sbin:/usr/bin. The default PATH can be set in /etc/de‐
       fault/cron (see cron(8)). The TZ, HOME, and SHELL environment variables
       are set to match those that are in effect in the crontab  file  at  the
       time.


       If  you  do not redirect the standard output and standard error of your
       commands, any generated output or errors are mailed to you.

   crontab Environment Variables
       The following variables are supported:

       HOME

           Allows the user to choose and alternative  directory  for  cron  to
           change directory to prior to running the command. For example:

             HOME=/var/tmp



       SHELL

           The  name of the shell to use to run subsequent commands. For exam‐
           ple:

             SHELL=/usr/bin/ksh



       TZ

           Allows the user to choose the time zone in which the  cron  entries
           are  run.  This affects both the environment of the command that is
           run and the timing of the entry. For example, to have your  entries
           run using the time zone for Iceland, use:

             TZ=Iceland




       Each  of these variables affects all of the lines that follow it in the
       crontab file, until it is reset by a  subsequent  line  resetting  that
       variable.  Hence,  it is possible to have multiple time zones supported
       within a single crontab file.


       The lines that are not setting these environment variables are the same
       as crontab entries that conform to the UNIX standard and are  described
       elsewhere in this man page.

   Setting cron Jobs Across Timezones
       The  default time zone of the cron daemon sets the systemwide time zone
       for cron entries. This, in turn, is by set by default systemwide as de‐
       scribed under TZ in the environ(7) manual page.


       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.

OPTIONS
       The following options are supported:

       -e    Edits a copy of the current user's crontab file,  or  creates  an
             empty  file  to  edit  if crontab does not exist. When editing is
             complete, the file is installed as the user's crontab file.

             The environment variable EDITOR determines which  editor  is  in‐
             voked  with  the  -e option. All crontab jobs should be submitted
             using crontab. Do not add jobs by just editing the crontab  file,
             because cron is not aware of changes made this way.

             If  all  lines  in  the crontab file are deleted, the old crontab
             file is restored. The correct way to delete all lines is  to  re‐
             move the crontab file using the -r option.

             If  username  is  specified, the specified user's crontab file is
             edited, rather than the current user's  crontab  file.  This  can
             only be done by root or by a user with the solaris.jobs.admin au‐
             thorization.


       -l    Lists the crontab file for the invoking user. Only root or a user
             with  the solaris.jobs.admin authorization can specify a username
             following the -l option to list the crontab file of the specified
             user.


       -r    Removes a user's crontab from the crontab directory. Only root or
             a user with the solaris.jobs.admin authorization  can  specify  a
             username  following  the  -r option to remove the crontab file of
             the specified user.


EXAMPLES
       Example 1 Cleaning up Core Files



       This example cleans up core files every weekday morning at 3:15 am:




         15 3 * * 1-5 find $HOME -name core 2>/dev/null | xargs rm -f


       Example 2 Mailing a Birthday Greeting



       This example mails a birthday greeting:


         0 12 14 2 * mailx john%Happy Birthday!%Time for lunch.


       Example 3 Specifying Days of the Month and Week



       This example runs a command on the first and fifteenth of  each  month,
       as well as on every Monday:


         0 0 1,15 * 1




       To  specify days by only one field, the other field should be set to *.
       For example:


         0 0 * * 1




       would run a command only on Mondays.

       Example 4 Using Environment Variables



       The following entries take advantage of crontab support for certain en‐
       vironment variables.


         TZ=GMT
         HOME=/local/home/user
         SHELL=/usr/bin/ksh
         0 0 * * * echo $(date) >        midnight.GMT
         TZ=US/Pacific
         0 0 * * * echo $(date) >        midnight.PST
         TZ=US/Eastern
         HOME=/local/home/myuser
         SHELL=/bin/csh




       The preceding entries allow two jobs to run. The first one would run at
       midnight in the GMT time zone and the second would run at  midnight  in
       the  PST time zone. Both would be run in the directory /local/home/user
       using the Korn shell. The file concludes with TZ, HOME, and  SHELL  en‐
       tries that return those variable to their default values.

ENVIRONMENT VARIABLES
       See  environ(7) for descriptions of the following environment variables
       that affect the execution of crontab: LANG, LC_ALL,  LC_CTYPE,  LC_MES‐
       SAGES, and NLSPATH.

   /usr/bin/crontab
       EDITOR    Determine  the  editor  to  be  invoked when the -e option is
                 specified. This is overridden  by  the  VISUAL  environmental
                 variable. The default editor is vi(1).


       PATH      The  PATH  in crontab's environment specifies the search path
                 used to find the editor.


       VISUAL    Determine the visual editor to be invoked when the -e  option
                 is  specified.  If VISUAL is not specified, then the environ‐
                 ment variable EDITOR is used. If that is not set, the default
                 is vi(1).


   /usr/xpg4/bin/crontab
       EDITOR    Determine the editor to be invoked  when  the  -e  option  is
                 specified. The default editor is /usr/xpg4/bin/vi.


   /usr/xpg6/bin/crontab
       EDITOR    Determine  the  editor  to  be  invoked when the -e option is
                 specified. The default editor is /usr/xpg6/bin/vi.


EXIT STATUS
       The following exit values are returned:

       0     Successful completion.


       >0    An error occurred.


FILES
       /etc/cron.d                 main cron directory


       /etc/cron.d/cron.allow      list of allowed users


       /etc/default/cron           contains cron default settings


       /etc/cron.d/cron.deny       list of denied users


       /var/cron/log               accounting information


       /var/spool/cron/crontabs    spool area for crontab


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:

   /usr/bin/crontab
       tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE  TYPEAT‐
       TRIBUTE VALUE _ Availabilitysystem/core-os _ Interface StabilityCommit‐
       ted _ StandardSee standards(7).


   /usr/xpg4/bin/crontab
       tab()  box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
       TRIBUTE VALUE _ Availabilitysystem/xopen/xcu4 _  Interface  StabilityS‐
       tandard


   /usr/xpg6/bin/crontab
       tab()  box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
       TRIBUTE VALUE _ Availabilitysystem/xopen/xcu6 _  Interface  StabilityS‐
       tandard


SEE ALSO
       atq(1),  atrm(1),  auths(1), ed(1), sh(1), vi(1), auth_attr(5), attrib‐
       utes(7), environ(7), standards(7), cron(8), su(8)

NOTES
       If you inadvertently enter the crontab command with  no  arguments,  do
       not attempt to get out with Control-d. This removes all entries in your
       crontab file. Instead, exit with Control-c.


       When  updating  cron, check first for existing crontab entries that can
       be scheduled close to the time of the update. Such entries can be  lost
       if  the  update  process  completes after the scheduled event. This can
       happen because, when cron is notified by crontab to update the internal
       view of a user's crontab file, it first removes the user's existing in‐
       ternal crontab and any internal scheduled events. Then it reads the new
       crontab file and rebuilds the internal crontab and  events.  This  last
       step takes time, especially with a large crontab file, and can complete
       after  an existing crontab entry is scheduled to run if it is scheduled
       too close to the update. To be safe, start a new job at least  60  sec‐
       onds after the current date and time.


       Simultaneous  modifications  of the same crontab file may lead to unex‐
       pected results.


       Care should be taken when adding TZ, SHELL and HOME  variables  to  the
       crontab  file  when  the crontab file could be shared with applications
       that do not expect those variables to be changed from the default.  Re‐
       setting  the  values  to  their defaults at the bottom of the file will
       minimize the risk of problems.

Oracle Solaris 11.4               6 Oct 2022                        crontab(1)
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