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CRONTAB(1)			 User Commands			    CRONTAB(1)

NAME
       crontab - maintains crontab files for individual users

SYNOPSIS
       crontab [-u user] file
       crontab [-u user] [-l | -r | -e] [-i] [-s]
       crontab -n [ hostname ]
       crontab -c

DESCRIPTION
       Crontab	is the program used to install, remove or list the 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 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(1) 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.

       Running cron jobs 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  cron  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  cron.  If neither of these files exists, only the super
       user is allowed to use cron.  Another way to restrict access to cron 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 in an environment variable.	 If it
       is not set by the user, the /tmp directory is used.

OPTIONS
       -u     Appends 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.	  Note
	      that  su(8)  may	confuse crontab, thus, when executing commands
	      under su(8) you should always use the -u option.	If no  crontab
	      exists  for  a  particular user, it is created for him the first
	      time the crontab -u command is used under his username.

       -l     Displays the current crontab on standard output.

       -r     Removes the current crontab.

       -e     Edits the current crontab using the editor specified by the VIS‐
	      UAL  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 /  replace‐
	      ment 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	 spec‐
	      ify 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.

SEE ALSO
       crontab(5), cron(8)

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

STANDARDS
       The crontab command conforms to IEEE Std1003.2-1992 (``POSIX'').	  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⟩

cronie				  2012-11-22			    CRONTAB(1)
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