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crontab(1)							    crontab(1)

       crontab - Submits a schedule of commands to cron

       crontab [file]

       crontab -l  | -v	 | -r  | -e [username]

       Interfaces  documented on this reference page conform to industry stan‐
       dards as follows:

       crontab:	 XCU5.0

       Refer to the standards(5) reference page	 for  more  information	 about
       industry standards and associated tags.

       Edits  a	 copy  of  your	 crontab entry.	 If the crontab entry does not
       exist, creates an empty entry to edit. The -e option invokes the editor
       specified  by  the  EDITOR environment variable, or uses /usr/bin/vi by
       default.	 The crontab command installs the new entry  when  editing  is

	      [Tru64  UNIX]  If	 username is specified, edits the file for the
	      specified user.  You must have  appropriate  privileges  to  use
	      this  option.   Displays	the  contents  of  your	 crontab file.
	      Removes the crontab file from  the  crontab  directory.	[Tru64
	      UNIX]  Displays  the  name of your crontab file and the date and
	      time at which you submitted it with crontab.

       Path name of file that contains crontab specifications  in  the	format

       The  crontab command copies the specified file or standard input if you
       do not specify a	 file  into  the  /var/spool/cron/crontabs  directory,
       which holds all users' crontab files.

       The  cron  command  runs	 commands according to the instructions in the
       crontab files.  The crontab files are named for users, and the commands
       in the files are run under the user's authority.	 For example, the com‐
       mands in the /var/spool/cron/crontabs/root  file	 are  run  under  root
       authority.   When  you  use  the	 crontab  command, the file under your
       authority is affected.  For example, if adm invokes the crontab -l com‐
       mand, the /var/spool/cron/crontabs/adm file is displayed.  If the user‐
       name argument is included, the specified user's crontab file is	listed
       and  edited rather than the current user's crontab file.	 You must have
       root privileges to specify the username argument.  By default,  the  vi
       editor is used.

       Note  that  the	file  /var/spool/cron/crontabs/root  contains  several
       entries that will run by default, such as the following command to back
       up  and	clean  the /var/adm/wtmp log file: 0 2 * * 0 /usr/bin/logclean
       /var/adm/wtmp > dev/null

       You can configure these default commands	 to  suit  your	 local	system

       After  cron  runs  commands  according  to the contents of your crontab
       file, it mails you the output from standard output and  standard	 error
       for  these  commands,  unless  you redirect standard output or standard


       When entries are made to a crontab file by using the  crontab  command,
       all previous entries in the file are removed.

       You  can	 use  the  crontab  command  if	 your user name appears in the
       /usr/lib/cron/cron.allow file.	If  that  file	does  not  exist,  the
       crontab command checks the /usr/lib/cron/cron.deny file to determine if
       you should be denied access to crontab.	The allow/deny	files  contain
       one  user  name per line.  If neither file exists, you can submit a job
       only if you are operating with superuser authority.

       Each crontab file entry consists of a line with six  fields,  separated
       by  spaces  and tabs.  The information in the fields specifies when the
       command runs and the name of the command.  The fields specify the  fol‐
       lowing:	The  first  field  specifies the minute (0 to 59).  The second
       field specifies the hour (0 to 23).  The third field specifies the  day
       of  the	month  (1 to 31).  The fourth field specifies the month of the
       year (1 to 12).	The fifth field specifies the day of the week  (0 to 6
       for  Sunday  to Saturday).  The sixth field specifies the shell command
       to be executed.

       You can specify the following values in the fields  that	 indicate  the
       time:  An integer (within the appropriate range of values) Two integers
       separated by a dash to indicate an inclusive range A list  of  integers
       separated by commas An asterisk to select all possible values

       You  can	 specify  the  days  on which the command is to execute in two
       fields (day of the month and day of the week).  You  can	 specify  both
       fields,	or  you	 can specify only one field.  To use only one field to
       specify the days, the other field should contain an asterisk  (*).   If
       both  methods  are used, the command is executed whenever either of the
       specifications is met.

       [Tru64 UNIX]  For example, the following entry runs command at midnight
       on the first and fifteenth days of each month, as well as every Monday:
       0 0 1,15 * 1 command

       The cron program runs the command named in the sixth field at the spec‐
       ified  date  and	 time.	If you include a percent sign (%) in the sixth
       field, cron treats everything that precedes it (in that field)  as  the
       command invocation, and makes all that follows it available to standard
       input, unless you escape the percent  sign  (\%)	 or  double  quote  it
       ("%").	An exclamation point (!) in the sixth field is translated as a
       newline character.

       The shell runs only the first line of the command field (up to  a  per‐
       cent  sign  or End-of-Line).  All other lines are made available to the
       command as standard input.

       The cron program invokes a subshell from your  $HOME  directory.	  This
       means that it will not run your file.  If you schedule a command to run
       when you are not logged in and you want to have commands in  your  run,
       you  must  explicitly  do so in the crontab file.  (For a more detailed
       discussion of how sh can be invoked, see the sh command.)

       The cron program supplies a default environment for every shell, defin‐
       ing HOME, LOGNAME, SHELL (=/usr/bin/sh), and PATH (=:/usr/bin).

       [Tru64 UNIX]  To submit commands to the cron daemon, invoke the crontab
       command with the -e option, or  perform	the  following	tasks:	[Tru64
       UNIX]  Become  the user that corresponds to the appropriate file in the
       /usr/spool/cron/crontabs directory.  For example, if you want to submit
       commands	 that  will  run under adm authority, become user adm.	[Tru64
       UNIX]  Use the crontab command with the -l option to copy the appropri‐
       ate  file  from	the  /usr/spool/cron/crontabs directory to a temporary
       file in your home directory.  For example, if you  are  user  adm,  you
       could   use  the	 following  command:  crontab  -l  >  temp_adm	[Tru64
       UNIX]  Edit the temporary file and add the commands you want to run  at
       a  specified  time.   [Tru64 UNIX]  Use the crontab command and specify
       the temporary file to submit the commands to the cron daemon.

       When entries are made to a  crontab  file,  all	previous  entries  are
       erased.	 If  your  user ID is associated with more than one user name,
       crontab uses the first user name that appears in the /etc/passwd	 file,
       regardless  of  which  user  name  you might actually be using.	[Tru64
       UNIX]  The file /usr/lib/cron is	 a  symbolic  link  to	/var/adm/cron.
       [Tru64  UNIX]  If  cron.allow  exists,  the  superuser's user name must
       appear there for that superuser to be able to use the command.

       The following exit values  are  returned:  Successful  completion.   An
       error occurred.

       The  following example writes the time to the console every hour on the
       hour: 0 * * * * echo The hour is `date`.	 >/dev/console	The  following
       example runs calendar at 6:30 a.m. every Monday, Wednesday, and Friday:
       30 6 * * 1,3,5 /usr/bin/calendar - The  following  example  writes  the
       contents	 of happyholidays.txt to all users logged in at 4:00 p.m. each
       Friday in December and each day between December	 10  and  December  31
       inclusive: 0 16 10-31 12 5 /usr/sbin/wall /var/tmp/happyholidays.txt

       The  following  environment  variables affect the execution of crontab:
       Determines the editor used with the  -e	option.	  Provides  a  default
       value for the internationalization variables that are unset or null. If
       LANG is unset or null, the corresponding value from the default	locale
       is  used.  If  any  of  the  internationalization  variables contain an
       invalid setting, the utility behaves as if none of  the	variables  had
       been defined.  If set to a non-empty string value, overrides the values
       of all the other internationalization variables.	 Determines the locale
       for the interpretation of sequences of bytes of text data as characters
       (for example, single-byte as opposed to multibyte characters  in	 argu‐
       ments).	 Determines the locale for the format and contents of diagnos‐
       tic messages written to standard error.	 Determines  the  location  of
       message catalogues for the processing of LC_MESSAGES.

       Main  cron  directory.	Directory  containing  the  crontab files adm,
       cronuucp, root, sys,and uucp.  List of allowed users.  List  of	denied
       users.	Log  of	 cron activity.	 Queue description file for at, batch,
       and cron.  Contains user information.  User profile.

       Commands:  at(1), cron(8),  mail(1),  mailx(1),	Bourne	shell  sh(1b),
       POSIX shell sh(1p)

       Files:  queuedefs(4)

       Standards:  standards(5)


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