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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/secu-
       rity/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 execut-
	      ing the command.	Note that su(8) may confuse crontab, thus,  when  executing  com-
	      mands  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 VISUAL or EDITOR envi-
	      ronment 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  host-
	      name  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.

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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