NAME
fcrontab - manipulate per-user fcrontab files
SYNOPSIS
fcrontab [ -c file ] [ -n ] file [ user | -u user ]
fcrontab [ -c file ] [ -n ] { -l | -r | -e | -z } [ user | -u user ]
fcrontab [ -h ]
DESCRIPTION
Fcrontab is the program intended to install, edit, list and remove the
tables used by fcron(8) daemon. As fcron internally uses a non-human
readable format (this is needed because fcron saves more informations
than the user gives, for example the time and date of next execution),
the user cannot edit directly his fcrontab (the one used by fcron).
When a user installs a fcrontab, the source file is saved in the spool
directory (/var/spool/fcron) to allow future editions, and a formatted
file is generated for the fcron daemon, which is signaled once about
ten seconds before the next minute for all changes made previously. The
daemon is not informed of the changes immediately but at most once a
minute to keep ill disposed users from blocking the daemon by
installing fcrontabs over and over (ie. denial of service attack). We
will call "fcrontab" the source file of the fcrontab in the following.
A user can install a fcrontab if he is listed in the /etc/fcron.allow
and not (unless by the keyword all) listed in /etc/fcron.deny (see
section "files" below). If neither fcron.allow nor fcron.deny exist,
all users are allowed. None of these files have to exist, but if they
do, the deny file takes precedence.
The first form of the command is used to install a new fcrontab file,
from any named file or from standard input if the pseudo-filename "-"
is given, replacing the previous one (if any): each user can have only
one fcrontab.
For instance, root can create a systemwide fcrontab file, say
/etc/fcrontab, and run "fcrontab /etc/fcrontab" to install the new
version after each change of the file. Or (s)he can create a new
fcrontab running a simple "fcrontab", and then maintain it using
"fcrontab -e". Same considerations apply to a non privileged user.
OPTIONS
-u user
Specify the user whose fcrontab will be managed, or "systab" for
the system fcrontab. Should only be used by root. If not given,
the fcrontab file of the user invoking fcrontab will be handled.
It may be useful since the su(8) command may confuse fcrontab.
Note: the to a ’-u user’.
-l List user’s current fcrontab to standard output.
-e Edit user’s current fcrontab using either the editor specified
by the environment variable VISUAL, or EDITOR if VISUAL is not
set. If none or them are set, /usr/bin/vi will be used.
-r Remove user’s fcrontab.
-z Reinstall user’s fcrontab from its source code. All informations
fcron may have kept in the binary fcrontab (such as the last
execution time and date) will be forgotten (ie. lost).
-n Ignore previous version. If this option is not given, fcron will
try to keep as much information as possible between old and new
version of the fcrontab (time and date of next execution, if job
is in serial queue, etc) if the line hasn’t been modified (same
fields, same shell command).
-c file
Make fcrontab use config file file instead of default config
file /etc/fcron.conf. To interact with a running fcron process,
fcrontab must use the same config file as the process. That way,
several fcron processes can run simultaneously on an only
system.
-d Run in debug mode. In this mode, many informational messages
will be output in order to check if anything went wrong.
-h Display a brief description of the options.
-V Display an informational message about fcrontab, including its
version and the license under which it is distributed.
RETURN VALUES
Fcrontab returns 0 on normal exit and 1 on error.
CONFORMING TO
Should be POSIX compliant.
FILES
/etc/fcron.conf
Configuration file for fcron, fcrontab and fcrondyn: contains
paths (spool dir, pid file) and default programs to use (editor,
shell, etc). See fcron.conf(5) for more details.
/etc/fcron.allow
Users allowed to use fcrontab and fcrondyn (one name per line,
special name "all" acts for everyone)
/etc/fcron.deny
Users who are not allowed to use fcrontab and fcrondyn (same
format as allow file)
/etc/pam.d/fcron (or /etc/pam.conf)
PAM configuration file for fcron. Take a look at pam(8) for more
details.
SEE ALSO
fcrontab(1),
fcrondyn(1),
fcrontab(5),
fcron.conf(5),
fcron(8).
If you’re learning how to use fcron from scratch, I suggest that you
read the HTML version of the documentation (if your are not reading it
right now! :) ): the content is the same, but it is easier to navigate
thanks to the hyperlinks.
AUTHOR
Thibault Godouet <fcron@free.fr>