crontab



CRONTAB(1)                  General Commands Manual                 CRONTAB(1)


NAME

     crontab - maintain crontab files for individual users


SYNOPSIS

     crontab [-u user] file
     crontab [-e | -l | -r] [-u user]


DESCRIPTION

     crontab is the program used to install, deinstall, or list the tables
     used to drive the cron(8) daemon.  Each user can have their own
     crontab(5), and though these are files in /var/cron/tabs, they are not
     intended to be edited directly.

     The first form of this command is used to install a new crontab from some
     named file, or standard input if the pseudo-filename `-' is given.

     If the /var/cron/cron.allow file exists, then you must be listed therein
     in order to use crontab.  If the /var/cron/cron.allow file does not exist
     but the /var/cron/cron.deny file does exist, then you must not be listed
     in the /var/cron/cron.deny file in order to use crontab.  If neither of
     these files exists then only the super user will be allowed to use
     crontab.  NOTE: if they exist, /var/cron/cron.allow and
     /var/cron/cron.deny must be readable by group crontab.  If crontab is
     unable to read the files, users will not be allowed to use crontab.

     The options are as follows:

     -e        Edit the current crontab using the editor specified by the
               VISUAL or EDITOR environment variables.  After you exit from
               the editor, the modified crontab(5) will be installed
               automatically.

     -l        Causes the current crontab to be displayed on standard output.

     -r        Causes the current crontab to be removed.

     -u user   Specifies the name of the user whose crontab(5) is to be
               edited.  If this option is not given, crontab examines ``your''
               crontab(5); i.e., the crontab of the person executing the
               command.  Note that su(1) can confuse crontab and that if you
               are running inside of su(1) you should always use the -u option
               for safety's sake.


ENVIRONMENT

     EDITOR, VISUAL
             Specifies an editor to use.  If both EDITOR and VISUAL are set,
             VISUAL takes precedence.  If neither EDITOR nor VISUAL are set,
             the default is vi(1).


FILES

     /var/cron/cron.allow  list of users allowed to use crontab
     /var/cron/cron.deny   list of users prohibited from using crontab
     /var/cron/tabs        directory of individual crontabs


DIAGNOSTICS

     A fairly informative usage message appears if you run it with a bad
     command line.


SEE ALSO

     at(1), crontab(5), cron(8)


STANDARDS

     The crontab utility is compliant with the IEEE Std 1003.1-2008
     (``POSIX.1'') specification.

     The flag [-u] is an extension to that specification.

     The flag [-e] is marked by IEEE Std 1003.1-2008 (``POSIX.1'') as being
     optional.

     The cron.allow/deny mechanism is marked by IEEE Std 1003.1-2008
     (``POSIX.1'') as being an X/Open System Interfaces option.


AUTHORS

     Paul Vixie <vixie@isc.org>

OpenBSD 5.9                    October 26, 2015                    OpenBSD 5.9

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