CRONTAB(1) General Commands Manual CRONTAB(1)
crontab - maintain crontab files for individual users
crontab [-u user] file
crontab [-e | -l | -r] [-u user]
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
-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.
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).
/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
A fairly informative usage message appears if you run it with a bad
at(1), crontab(5), cron(8)
The crontab utility is compliant with the IEEE Std 1003.1-2008
The flag [-u] is an extension to that specification.
The flag [-e] is marked by IEEE Std 1003.1-2008 ("POSIX.1") as being
The cron.allow/deny mechanism is marked by IEEE Std 1003.1-2008
("POSIX.1") as being an X/Open System Interfaces option.
Paul Vixie <email@example.com>
OpenBSD 6.2 October 26, 2015 OpenBSD 6.2
[Unix Hosting |
[Engineering & Automation |
Software Development |