utility is the program used to install, deinstall or list the tables
used to drive the
daemon in Vixie Cron.
Each user can have their own crontab, and though
these are files in
they are not intended to be edited directly.
file exists, then you must be listed therein in order to be allowed to use
file does not exist but the
file does exist, then you must
be listed in the
file in order to use this command.
If neither of these files exists, then
depending on site-dependent configuration parameters, only the super user
will be allowed to use this command, or all users will be able to use this
The format of these files is one username per line,
with no leading or trailing whitespace.
Lines of other formats will be ignored,
and so can be used for comments.
The first form of this command is used to install a new crontab from some
named file or standard input if the pseudo-filename
The following options are available:
Specify the name of the user whose crontab is to be
If this option is not given,
crontab, i.e., the crontab of the person executing the
and that if you are running inside of
you should always use the
option for safety's sake.
Display the current crontab on standard output.
Remove the current crontab.
By default the
option prompts for confirmation, adding the
option will attempt to remove the current crontab without confirmation.
Edit the current crontab using the editor specified by
The specified editor
edit the file in place;
any editor that unlinks the file and recreates it cannot be used.
After you exit
from the editor, the modified crontab will be installed automatically.