Provided by: cronie_1.7.1-1_amd64 bug

NAME

       crontab - maintains crontab files for individual users

SYNOPSIS

       crontab [-u user] <file | ->
       crontab [-T] <file | ->
       crontab [-u user] <-l | -r | -e> [-i] [-s]
       crontab -n [ hostname ]
       crontab -c
       crontab -V

DESCRIPTION

       Crontab  is  the program used to install a crontab table file, remove or list the existing
       tables used to serve the cron(8) daemon.  Each user can have their own crontab, and though
       these  are files in /var/spool/, they are not intended to be edited directly.  For SELinux
       in MLS mode, you can define more crontabs for  each  range.   For  more  information,  see
       selinux(8).

       In   this   version   of   Cron   it   is   possible   to  use  a  network-mounted  shared
       /var/spool/cron/crontabs across a cluster of hosts and specify that only one of the  hosts
       should run the crontab jobs in the particular directory at any one time.  You may also use
       crontab from any of these hosts to edit the same shared set of crontab files, and  to  set
       and query which host should run the crontab jobs.

       Scheduling  cron  jobs with crontab can be allowed or disallowed for different users.  For
       this purpose, use the cron.allow and cron.deny files.  If the cron.allow  file  exists,  a
       user  must  be listed in it to be allowed to use crontab.  If the cron.allow file does not
       exist but the cron.deny file does exist, then a user must not be listed in  the  cron.deny
       file  in  order to use crontab.  If neither of these files exist, then only the super user
       is allowed to use crontab.

       Another way to restrict the  scheduling  of  cron  jobs  beyond  crontab  is  to  use  PAM
       authentication  in  /etc/security/access.conf  to  set  up  users,  which  are  allowed or
       disallowed to use crontab or modify system cron jobs in the /etc/cron.d/ directory.

       The temporary directory can be set using the environment variable $TMPDIR.  If it  is  not
       set by the user, the /tmp directory is used.

       When  listing  a  crontab on a terminal the output will be colorized unless an environment
       variable NO_COLOR is set.

       On edition or deletion of the crontab, a backup of the  last  crontab  will  be  saved  to
       $XDG_CACHE_HOME/crontab/crontab.bak or $XDG_CACHE_HOME/crontab/crontab.<user>.bak if -u is
       used.  If the XDG_CACHE_HOME environment variable is not set, $HOME/.cache  will  be  used
       instead.

OPTIONS

       -u     Specifies  the name of the user whose crontab is to be modified.  If this option is
              not used, crontab  examines  "your"  crontab,  i.e.,  the  crontab  of  the  person
              executing  the  command.  If no crontab exists for a particular user, it is created
              for them the first time the crontab -u command is used under their username.

       -T     Test the crontab file syntax without installing it.  Once an issue  is  found,  the
              validation  is  interrupted, so this will not return all the existing issues at the
              same execution.

       -l     Displays the current crontab on standard output.

       -r     Removes the current crontab.

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

       -i     This option modifies the -r option to prompt the user for a 'y/Y'  response  before
              actually removing the crontab.

       -s     Appends  the current SELinux security context string as an MLS_LEVEL setting to the
              crontab file before editing  /  replacement  occurs  -  see  the  documentation  of
              MLS_LEVEL in crontab(5).

       -n     This  option  is relevant only if cron(8) was started with the -c option, to enable
              clustering support.  It is used to set the host in the cluster which should run the
              jobs  specified  in  the  crontab  files  in  the  /var/spool/cron directory.  If a
              hostname is supplied, the host whose hostname returned  by  gethostname(2)  matches
              the supplied hostname, will be selected to run the selected cron jobs subsequently.
              If there is no  host  in  the  cluster  matching  the  supplied  hostname,  or  you
              explicitly  specify  an  empty  hostname, then the selected jobs will not be run at
              all.  If the  hostname  is  omitted,  the  name  of  the  local  host  returned  by
              gethostname(2)  is  used.  Using this option has no effect on the /etc/crontab file
              and the files in the /etc/cron.d directory, which are always  run,  and  considered
              host-specific.  For more information on clustering support, see cron(8).

       -c     This  option  is only relevant if cron(8) was started with the -c option, to enable
              clustering support.  It is used to query which host in the cluster is currently set
              to  run  the jobs specified in the crontab files in the directory /var/spool/cron ,
              as set using the -n option.

       -V     Print version and exit.

CAVEATS

       The files cron.allow and cron.deny cannot be used to restrict the execution of cron  jobs;
       they  only  restrict the use of crontab.  In particular, restricting access to crontab has
       no effect on an existing crontab of a user. Its jobs will continue to  be  executed  until
       the crontab is removed.

       The files cron.allow and cron.deny must be readable by the user invoking crontab.  If this
       is not the case, then they are treated as non-existent.

SEE ALSO

       crontab(5), cron(8)

FILES

       /etc/cron.allow
       /etc/cron.deny

STANDARDS

       The crontab command conforms to IEEE Std1003.2-1992 (``POSIX'') with  one  exception:  For
       replacing  the  current crontab with data from standard input the - has to be specified on
       the command line if the standard input is a TTY.  This new  command  syntax  differs  from
       previous versions of Vixie Cron, as well as from the classic SVR3 syntax.

DIAGNOSTICS

       An informative usage message appears if you run a crontab with a faulty command defined in
       it.

AUTHOR

       Paul Vixie ⟨vixie@isc.org⟩
       Colin Dean ⟨colin@colin-dean.org