anacron; man page

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SYNOPSIS
       anacron  [-s]  [-f]  [-n] [-d] [-q] [-t anacrontab] [-S spooldir] [job]
       ...
       anacron [-S spooldir] -u [-t anacrontab] [job] ...
       anacron [-V|-h]
       anacron -T [-t anacrontab]

DESCRIPTION
       Anacron can be used to execute commands periodically, with a  frequency
       specified in days.  Unlike cron(8), it does not assume that the machine
       is running continuously.  Hence, it can be used on machines that aren’t
       running 24 hours a day, to control daily, weekly, and monthly jobs that
       are usually controlled by cron.

       When executed, Anacron reads a list of jobs from a configuration  file,
       normally  /etc/anacrontab  (see anacrontab(5)).  This file contains the
       list of jobs that Anacron controls.  Each job entry specifies a  period
       in  days, a delay in minutes, a unique job identifier, and a shell com‐
       mand.

       For each job, Anacron checks whether this job has been executed in  the
       last  n  days,  where  n is the period specified for that job.  If not,
       Anacron runs the job’s shell command, after waiting for the  number  of
       minutes specified as the delay parameter.

       After  the  command exits, Anacron records the date in a special times‐
       tamp file for that job, so it can know when to execute it again.   Only
       the date is used for the time calculations.  The hour is not used.

       When there are no more jobs to be run, Anacron exits.

       Anacron  only  considers  jobs  whose  identifier,  as specified in the
       anacrontab matches any of the  job  command-line  arguments.   The  job
       arguments  can be shell wildcard patterns (be sure to protect them from
       your shell with adequate quoting).  Specifying  no  job  arguments,  is
       equivalent to specifying "*"  (That is, all jobs will be considered).

       Unless  the  -d option is given (see below), Anacron forks to the back‐
       ground when it starts, and the parent process exits immediately.

       Unless the -s or -n options are given, Anacron starts jobs  immediately
       when  their  delay  is  over.   The execution of different jobs is com‐
       pletely independent.

       If a job generates any output on its standard output or standard error,
       the  output is mailed to the user running Anacron (usually root), or to
       the address  contained  by  the  MAILTO  environment  variable  in  the
       crontab, if such exists. If the LOGNAME environment variable is set, it
       will be used as From: field.

       Informative messages about what Anacron is doing are sent to syslogd(8)
       under  facility cron, priority notice.  Error messages are sent at pri‐
              before the previous one finished.

       -n     Run   jobs   now.    Ignore  the  delay  specifications  in  the
              /etc/anacrontab file.  This options implies -s.

       -d     Don’t fork to the background.  In this mode, Anacron will output
              informational  messages to standard error, as well as to syslog.
              The output of jobs is mailed as usual.

       -q     Suppress messages to standard error.  Only applicable with -d.

       -t anacrontab
              Use specified anacrontab, rather than the default

       -T     Anacrontab testing. The configuration file will  be  tested  for
              validity.  If  there  is  an error in the file, an error will be
              shown and anacron will return 1. Valid anacrontabs  will  return
              0.

       -S spooldir
              Use  the  specified spooldir to store timestamps in. This option
              is required for users who wish to run anacron themselves.

       -V     Print version information, and exit.

       -h     Print short usage message, and exit.

SIGNALS
       After receiving a SIGUSR1 signal, Anacron waits for  running  jobs,  if
       any,  to  finish  and  then  exits.   This  can be used to stop Anacron
       cleanly.

NOTES
       Make sure that  the  time-zone  is  set  correctly  before  Anacron  is
       started.   (The  time-zone  affects  the date).  This is usually accom‐
       plished by setting the TZ environment  variable,  or  by  installing  a
       /usr/lib/zoneinfo/localtime file.  See tzset(3) for more information.

       Timestamp  files  are  created  in  the spool directory for each job in
       anacrontab. These are  never  removed  automatically  by  anacron,  and
       should be removed by hand if a job is no longer being scheduled.

FILES
       /etc/anacrontab
              Contains  specifications  of jobs.  See anacrontab(5) for a com‐
              plete description.

       /var/spool/anacron
              This directory is used by Anacron for storing timestamp files.

SEE ALSO
       anacrontab(5), cron(8), tzset(3)
       Anacron  was  originally conceived and implemented by Christian Schwarz
       <schwarz@monet.m.isar.de>.

       The  current  implementation  is  a  complete  rewrite  by  Itai   Tzur
       <itzur@actcom.co.il>.

       The    code    base    was    maintained   by   Sean   ’Shaleh’   Perry
       <shaleh@(debian.org|valinux.com)>.

       Since 2004, it is maintained by Pascal  Hakim  <pasc@(debian.org|redel‐
       lipse.net)>.




Pascal Hakim                      2004-07-11                        ANACRON(8)
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