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FCRONTAB(5)                                                        FCRONTAB(5)

       fcrontab - tables for driving fcron

       A fcrontab is a file containing all tables used by the fcron(8) daemon.
       In other words, it is the means for a user to tell the daemon  "execute
       this  command  at  this  moment". Each user has his own fcrontab, whose
       commands are executed as his owner (only root can run a job as  another
       using the option runas (see below)).

       Blank  lines,  line  beginning by a hash sign (#) (which are considered
       comments), leading blanks and tabs are ignored. Each line in a fcrontab
       file can be either

       o an environment setting,

       o an option setting,

       o entries based on elapsed system up time,

       o entries based on absolute time (like normal crontab entries), or

       o entries run periodically.

       Any  logical  line (an entry or an assignment) can be divided into sev-
       eral real lines (the lines which end by a newline character) by placing
       a backslash (\) before the newline character (\n).

       The environment settings are of the form

              name = value

       where the blanks around equal-sign (=) are ignored and optional. Trail-
       ing blanks are also ignored, but you can  place  the  value  in  quotes
       (simple or double, but matching) to preserve any blanks in the value.

       When  fcron executes a command, it always sets USER, HOME, and SHELL as
       defined in /etc/passwd for the owner of the  fcrontab  from  which  the
       command  is  extracted. HOME and SHELL may be overridden by settings in
       the fcrontab, but USER may not.  Every  other  environment  assignments
       defined  in  the  user  fcrontab are then made, and the command is exe-

       Plus, the special variable MAILTO allows you to tell fcron to  whom  it
       has  to  mail the command's output. Note that MAILTO is in fact equiva-
       lent to a global declaration of the option mailto (see  below).  It  is
       only  used  for  backward  compatibility,  so you should use the option
       mailto directly.

       The entries of commands which have to be run once every  m  minutes  of
       fcron's  execution (which is normally the same as m minutes of system's
       execution) are of the form

       @options frequency command

       where frequency is a time value of the form value*multiplier+value*mul-
       tiplier+...+value-in-minutes  as "12h02" or "3w2d5h1".  The first means
       "12 hours and 2 minutes of fcron execution" while the second  means  "3
       weeks, 2 days, 5 hours and 1 minute of fcron execution". The only valid
       multipliers  are:  "VALID  TIME  MULTIPLIERS"   meaning:   multipliers:
       months  (4  weeks):  m       weeks  (7 days): w      days (24 hours): d
       hours (60 minutes): h  seconds: s

       In place of options, user can put a time value: it will be  interpreted
       as @first(<time>). If first option is not set, the value of "frequency"
       is used.

       This kind of entry does not guarantee a time and date of execution  (as
       the  job is delayed at each startup by the time elapsed since the shut-
       down), but should be useful for jobs depending on the number of  things
       done  by  the  users  (for  instance,  the  filesystem should better be
       checked after a certain amount of use by the users rather than every  x
       days,  as  the  system  may run from 1 day to x days during that x days

       The time remaining before next execution is saved  every  1800  seconds
       (to  limit damages caused by a crash) and when fcron exits after having
       received a SIGTERM signal, i.e. when systems go down. Thus,  this  kind
       of entries is particularly useful for systems that don't run regularly.
       The syntax being very simple, it may also useful for tasks which  don't
       need to be run at a specific time and date.

       See  also:  options  first, mail, nolog, serial, lavg, nice, runas (see

       # Get our mails every 30 minutes
       @ 30 getmails -all

       # make some security tests every 48 hours of system up time,
       # force a mail to be sent to root even if there is no output
       @mailto(root),forcemail 2d /etc/security/msec/cron-sh/security.sh

       The second type of fcrontab's entries begins by an optional "&",  which
       can  be  immediately  followed  by an optional number defining the fre-
       quency of execution (this is equivalent to option runfreq) or a  decla-
       ration  of  options; it has five time and date fields, and a shell com-
       mand :

       &options min hrs day-of-month month day-of-week command

       Note that the shell command may be preceded by a user  name,  which  is
       equivalent  to  runas(<user>): as it is only here for backward compati-
       bility you should use option runas (see below) instead.  The  frequency
       is  interpreted  as: "run this command after x matches of time and date
       fields". The time and date fields are: "TIME AND  DATE  FIELDS"  field:
       allowed  values:       minute:  0-59      hour: 0-23      day of month:
       1-31      month: 1-12 (or names, see below)      day of  week:  0-7  (0
       and 7 are both Sunday, or names)

       A  field  is  always  filled  by  either an asterisk (*), which acts as
       "first-last" range, a single number or a list.

       List are numbers or range separated  with  commas  (,).  For  instance:

       Ranges  of  number  are  of the form "<begin>-<end>", where "begin" and
       "end" are included. For example, "3-5" specifies the values 3, 4 and 5.
       You  can  also  add  an optional "/number" to a range, where the number
       specifies skips of the number's value through the range.  For  example,
       "0-23/2"  can  be  used in the hours field to specify command execution
       every other hour. Finally, one or several "~number"  can  be  added  to
       turn  off  some  specific  values in a range. For example, "5-8~6~7" is
       equivalent to "5,8". The final form of a field is:


       where the letters are integers.

       You can also use an asterisk (*) in a field. It acts for  "first-last".
       For  example, a "*" in the field minute means all minutes from minute 0
       down to minute 59.

       Ranges can be included in a list as  a  single  number.  For  instance:

       Names  can also be used for the "month" and "day of week" fields. To do
       so, use the first three letters of the particular day  or  month  (case
       doesn't  matter).  Please  note that names are used exactly as numbers:
       you can use them in a list or a range.

       If a day of month and a day of week are given, the command will execute
       only when both match with the current time and date unless option dayor
       is set. For example, with the line

       5 10 31 * 7 echo ''
       echo will only be executed days which are  a  Sunday  AND  a  31th,  at

       See  also:  options dayor, bootrun, runfreq, mail, nolog, serial, lavg,
       nice, runas (see below).

       # run mycommand at 12:05, 12:35, 13:05, 13:35,
       # 14:05 *and* 14:35 everyday
       & 05,35 12-14 * * * mycommand -u me -o file

       # get mails every hour past 20, 21, 22, and 24 minutes.
       20-24~23 * * * * getmail

       # save our work of the day every night at 03:45 with a low priority
       # unless we are sunday, mail the output to jim and run that job
       # at startup if computer was down at 03:45
       &nice(10),mailto(jim),bootrun 45 03 * * *~0 "save --our work"

       The third type of fcrontab's entries begin by a "%", followed by a key-
       word from one of 3 different lists, and optional options.

       Those keywords are:

       hourly , daily , monthly , weekly

       Those keywords tell fcron to run the command once from the beginning of
       the corresponding time interval to the end of  that  time  interval.  A
       time  interval is, for example, the time from Monday 16:20 to Wednesday
       01h43.  For instance, the keyword weekly tells fcron to run  a  command
       once between Monday and Sunday each week.

       With  this  two kind of keywords, user must give the needed time fields
       (as defined in "Entries based on time and date" (see above)) to specify
       when the command should be run during each time interval:

       "NEEDED TIME FIELDS FOR EACH KEYWORD" Keywords: must be followed by the
       fields:  hourly, midhourly:  minutes. daily, middaily, nightly, weekly,
       midweekly:  minutes and hours. monthly, midmonthly:  minutes, hours and

       They are similar to the "*ly" ones:

       midhourly , middaily , nightly , midmonthly , midweekly

       They work exactly has the "*ly" keywords, except that the  time  inter-
       vals  are  defined  from  middle  to  middle of the corresponding "*ly"
       intervals: midweekly will run a command once from Thursday  to  Wednes-
       day. Note that nightly is equivalent to middaily.

       For example:

       %nightly,mail(no) * 21-23,3-5 echo "a nigthly entry"

       will run the command once each night either between 21:00 and 23:59, or
       between 3:00 and 5:59 (it will run as soon as possible. To change that,
       use  option  random) and won't send mail (because option mail is set to

       See also: options lavg,  noticenotrun,  strict,  mail,  nolog,  serial,
       nice, runas, random (see below).

       They are:

       mins , hours , days , mons , dow

       Those keywords act differently, as follows:

       run this command once during EACH time interval specified, ignoring the
       fields below the keyword in the time interval definition (a hours  pre-
       vents  the  mins field to be considered as a time interval, but it will
       be used to determine when the line should be run  during  an  interval:
       see the note below) (dow means "day of week").

       Such  a  keyword is followed by 5 time and date fields (the same fields
       used for a line based on absolute time (see above)). Furthermore, there
       must be some non-matching time and dates in the lines with that kind of
       keyword (i.e. the following is not allowed :

       %hours * 0-23 * * * echo "INCORRECT line!"

       %hours * 0-22 * * * echo "Ok."
       is allowed).


              a single number in a field is considered as a time interval:

              %mins 15 2-4 * * * echo
              will run at 2:15, 3:15 AND 4:15 every day.

              But all fields below the keywords are ignored in  time  interval

              %hours 15 2-4 * * * echo
              will run only ONCE either at 2:15, 3:15 OR 4:15.

       See also: option random (see below).

       The  options  can be set either for every line below the declaration or
       for an individual line. In the first case, the setting  is  done  on  a
       whole  line immediately after an exclamation mark (!), while it is done
       after a "&", a "%" or a "@" depending on the type of scheduling in  the
       second  case.  Note  that an option declaration in a schedule overrides
       the global declaration of that same option.

       Options are separated by commas (,) and their arguments,  if  any,  are
       placed  in parentheses ("(" and ")") and separated by commas. No spaces
       are allowed. A declaration of options is of the form


       where option is either the name of an option or its  abbreviation.  The
       options  are  (default  value  in  parentheses):  "VALID  OPTIONS  IN A


       b      boolean(false)

              Run a &-line at fcron's startup if it should have be run  during
              system down time.

       dayand boolean(true)

              Perform a logic AND between week and month day.

              See also: options dayor.

       dayor  boolean(false)

              Perform a logic OR between week and month day.

              See also: options dayand.

       exesev boolean(false)

              Can a job be executed several times simultaneously ?

              See also: options serialonce, lavgonce.


       f      time-value

              Delay  before  first  execution of a job based on system up time
              ("@"-lines). Useful in the following case: you have several jobs
              running,  say,  every hour. By setting different first value for
              each job, you can avoid them to  run  simultaneously  everytime.
              You  can also set it to 0, which is useful when used in conjunc-
              tion with option volatile.


              Mail output even if zero-length.

              See also: options mail, mailto, nolog.

       lavg   real(0) real(0) real(0)

              Set the values of the 1, 5 and 15-minute (in this order)  system
              load  average  values below which the job should run. The values
              have a maximum of 1 decimal (i.e. "2.3"): if there are more than
              1  decimal,  the  value  will  be round off. Set a value to 0 to
              ignore the corresponding load average (or all of the  values  to
              run the job regardless of the load average).

              See also: options lavg1, lavg5, lavg15, until, lavgonce, lavgor,
              lavgand, strict, noticenotrun.



       lavg15 real(0)

              Set the threshold of, respectively, the 1, 5 or 15 minutes  sys-
              tem  load average value. Set one of them to 0 to ignore the cor-
              responding load average.

              See also: options lavg.


              Perform a logic AND between the 1, 5 and 15 minutes system  load
              average values.

              See also: options lavg, lavgor.


              Can a job be queued several times in lavg queue simultaneously?

              See also: options lavg.

       lavgor boolean(false)

              Perform  a  logic OR between the 1, 5 and 15 minutes system load
              average values.

              See also: options lavg, lavgand.


       m      boolean(true)

              Mail output (if any) or not.

              See also: options mailto, forcemail, nolog.

       mailto email-address(name of file's owner)

              Mail output (if needed) to "email-address". It can be  either  a
              single  user-name  or  a fully qualified email address. A mailto
              declared and empty (string "") is equivalent to "mail(false)".

              See also: options mail, forcemail, nolog.


       n      nice-value

              Change job priority. A nice-value is an integer from -20  (high-
              est priority) to 19 (lowest) (only root is allowed to use a neg-
              ative value with this option).

       nolog  boolean(false)

              If set to true, log only errors for  the  corresponding  job(s).
              May be useful for jobs running very often, and/or to reduce disk
              access on a laptop.

              See also: options mail, mailto, forcemail.


              Should fcron mail user to report the non-execution of a %-job or
              a  &-job?  (because  of system down state for both or a too high
              system load average for the latter)

              See also: options lavg, strict.

       random boolean(false)

              In a line run periodically, this option  answers  the  question:
              should  this job be run as soon as possible in its time interval
              of execution (safer), or should fcron set a random time of  exe-
              cution  in  that time interval? Note that if this option is set,
              the job may not run if fcron is not  running  during  the  whole
              execution  interval.  Besides,  you  must  know  that the random
              scheme may be quite easy to guess for skilled people: thus,  you
              shouldn't  rely  on this option to make important things secure.
              However, it shouldn't be a problem for most uses.

       reset  boolean

              Reset all the options to default.

       runas  user-name

              Run with "user-name" permissions and environment (only  root  is
              allowed to use this option).


       r      integer

              Run  every  "runfreq"  matches of time and date. (this option is
              ignored for lines based on elapsed system up time).


       s      boolean(false)

              Fcron runs at most 1 serial  jobs  (ie.  for  which  the  option
              serial  is set to true), and the same number of lavg serial jobs
              (ie. for which both option serial and lavg (or lavg1 or lavg5 or
              lavg15) are set to true) simultaneously. This value may be modi-
              fied by fcron's option -m. This option is especially useful when
              used with big jobs in order to limit the system overload.

              See also: options serialonce, lavg.


              Can  a  job  be  queued several times in serial queue simultane-

              See also: options exesev, lavgonce.

       stdout boolean(false)

              If fcron is running in the foreground, then also let jobs  print
              to stderr/stdout instead of mailing or discarding it.

              See also: fcron's option --once in fcron(8).

       strict boolean(true)

              When a lavg %-job is at the end of a time interval of execution,
              should it be removed from the lavg queue (strict(true),  so  the
              job  is  not  run) or be let there until the system load average
              allows its execution (strict(false))?

              See also: options lavg, noticenotrun.

              timezone-name(time zone of the system)

              Run the job in the given time zone. timezone-name  is  a  string
              which is valid for the environment variable TZ: see the documen-
              tation  of  your  system  for  more   details.   For   instance,
              "Europe/Paris"  is  valid on a Linux system. This option handles
              daylight saving time changes correctly.

              Please note that if you give an  erroneous  timezone-name  argu-
              ment,  it  will be SILENTLY ignored, and the job will run in the
              time zone of the system.

              WARNING: do *not* use option timezone and option tzdiff simulta-
              neously!  There  is  no  need to do so, and timezone is cleverer
              than tzdiff.

              See also: options tzdiff.

       tzdiff integer(0)

              WARNING: this option is deprecated: use option timezone instead!

              Time zone difference (in hours, between -24 and 24) between  the
              system  time, and the local real time. This option allows a user
              to define its & and %-lines in the local time.  Note  that  this
              value  is set for a whole fcrontab file, and only the last defi-
              nition is taken into account. tzdiff is quite stupid: it doesn't
              handle  daylight  saving changes, while option timezone does, so
              you should use the latter.

              See also: options timezone.

       until  time-value(0)

              Set the timeout of the waiting of the wanted system load average
              values.  If  the timeout is exceeded, the job runs no matter the
              load average. Set until to 0 to remove the timeout.

              See also: options lavg.


              When set to true, the job is based on  a  "volatile"  system  up
              time, i.e. restart counting each time fcron is started, which is
              useful when fcron is started  by  a  script  running  only,  for
              instance,  during  a dialup connection: the "volatile" system up
              time then refers to the dialup connection  time.  You  may  also
              want to use option first if you use fcron that way.

              See  also:  options first, stdout, lines based on elapsed system
              up time, fcron's option --once in fcron(8).

       A boolean argument can be non-existent, in which case  parentheses  are
       not used and it means true; the string "true", "yes" or 1 to mean true;
       and the string "false", "no" or 0 to mean false. See above for explana-
       tions  about  time  value  (section "entries based on elapsed system up

       Note that dayand and dayor are in fact the same option: a  false  value
       to  dayand  is  equivalent to a true to dayor, and reciprocally a false
       value to dayor is equivalent a true value to dayand. It is the same for
       lavgand and lavgor.

       Note  a  special  case  to be handled: A job should be entered into the
       serial queue, *but* the previous entry for this job has not  been  com-
       pleted  yet, because of high system load or some external event. Option
       serialonce answers the question: should the new entry  of  the  job  be
       ignored?  This  way  one can distinguish between jobs required to run a
       certain number of times, preferably at specified times, and tasks to be
       performed  irrespective  of  their  number (-> serialonce(true)), which
       make the system respond faster.

       The same considerations apply for the load average queue,  and  can  be
       expressed with option lavgonce.

       Moreover,  if  the  serial or the lavg queue contains respectively more
       than 30 and 30 jobs, any new job is refused and not  run  to  avoid  an
       overwhelming  of  system  resources.  In this case, an error message is
       logged through syslog.

       Finally, if jobs remain in the lavg or serial queues when fcron  stops,
       they  will  be  put  once  in the corresponding queue on startup (their
       order may not be conserved).


       # use /bin/bash to run commands, ignoring what /etc/passwd says

       # mail output to thib, no matter whose fcrontab this is

       # define a variable which is equivalent to " Hello thib and paul! "
       # here the newline characters are escaped by a backslash (\)
       # and quotes are used to force to keep leading and trailing blanks
       TEXT= " Hello\
        thib and\
        paul! "

       # we want to use serial but not bootrun:

       # run after five minutes of execution the first time,
       # then run every hour
       @first(5) 1h   echo "Run every hour"

       # run every day
       @ 1d echo "fcron daily"

       # run once between in the morning and once in the afternoon
       #  if systems is running at any moment of these time intervals
       %hours * 8-12,14-18 * * * echo "Hey boss, I'm working today!"

       # run once a week during our lunch
       %weekly * 12-13 echo "I left my system on at least once \
        at lunch time this week."

       # run every Sunday and Saturday at 9:05
       5 9 * * sat,sun echo "Good morning Thibault!"

       # run every even days of march at 18:00, except on 16th
       0 18 2-30/2~16 Mar * echo "It's time to go back home!"

       # the line above is equivalent to
       & 0 18 2-30/2~16 Mar * echo "It's time to go back home!"

       # reset options to default and set runfreq for lines below

       # run once every 7 matches (thanks to the declaration above),
       # so if system is running every day at 10:00, this will be
       # run once a week
       & 0 10 * * * echo "if you got this message last time 7 days ago,\
        this computer has been running every day at 10:00 last week.\
        If you got the message 8 days ago, then the system has been down \
        one day at 10:00 since you got it, etc"

       # wait every hour for a 5 minutes load average under 0.9
       @lavg5(0.9) 1h echo "The system load average is low"

       # wait a maximum of 5 hours every day for a fall of the load average
       @lavgand,lavg(1,2.0,3.0),until(5h) 1d echo "Load average is going down"

       # wait for the best moment to run a heavy job
       @lavgor,lavg(0.8,1.2,1.5),nice(10) 1w echo "This is a heavy job"

       # run once every night between either 21:00 and 23:00 or
       #   between 3:00 and 6:00
       %nightly,lavg(1.5,2,2) * 21-23,3-6 echo "It's time to retrieve \
        the latest release of Mozilla!"

              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.

              Users allowed to use fcrontab and fcrondyn (one name  per  line,
              special name "all" acts for everyone)

              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






       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.

       Thibault Godouet <fcronATfree.fr>

02/06/2006                      06 fvrier 2006                     FCRONTAB(5)