maintain crontab files for individual
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
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
they exist, /var/cron/cron.allow and
/var/cron/cron.deny must be readable by group
crontab is unable to read the files,
users will not be allowed to use
The options are as follows:
- Edit the current crontab using the editor specified by the
EDITORenvironment variables. After you exit from the editor, the modified crontab(5) will be installed automatically.
- Causes the current crontab to be displayed on standard output.
- Causes the current crontab to be removed.
- Specifies the name of the user whose
crontab(5) is to be edited. If this option is not given,
crontabexamines “your” crontab(5); i.e., the crontab of the person executing the command. Note that su(1) can confuse
crontaband that if you are running inside of su(1) you should always use the
-uoption for safety's sake.
- Specifies an editor to use. If both
VISUALtakes precedence. If neither
VISUALare set, the default is vi(1).
- list of users allowed to use crontab
- list of users prohibited from using crontab
- directory of individual crontabs
A fairly informative usage message appears if you run it with a bad command line.
at(1), crontab(5), cron(8)
crontab utility is compliant with the
IEEE Std 1003.1-2008 (“POSIX.1”)
The flag [
-u] is an extension to that
The flag [
-e] is marked by
IEEE Std 1003.1-2008 (“POSIX.1”) as
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>