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, 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 signaled immediately
to keep ill disposed users from blocking the daemon by installing
fcrontabs over and over. 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
'user' in the synopsys is equivalent
to a '-uuser'.
-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.
