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ANACRON(8)		     Anacron Users' Manual		    ANACRON(8)

NAME
       anacron - runs commands periodically

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

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	/usr/local/etc/anacrontab (see anacrontab(5)).	This file con-
       tains 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 command.

       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	 time-
       stamp 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 ar-
       guments 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).

       Informative messages about what Anacron is doing	are sent to syslogd(8)
       under  facility cron, priority notice.  Error messages are sent at pri-
       ority error.

       "Active"	jobs (i.e. jobs	that Anacron already decided to	 run  and  now
       wait  for  their	 delay to pass,	and jobs that are currently being exe-
       cuted by	Anacron), are "locked",	so that	other copies of	Anacron	 won't
       run them	at the same time.

OPTIONS
       -f     Force execution of the jobs, ignoring the	timestamps.

       -u     Only update the timestamps of the	jobs, to the current date, but
	      don't run	anything.

       -s     Serialize	execution of jobs.  Anacron will not start a  new  job
	      before the previous one finished.

       -n     Run  jobs	 now.  Ignore the delay	specifications in the /usr/lo-
	      cal/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

       -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.

FILES
       /usr/local/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)

       The Anacron README file.

BUGS
       Anacron never removes timestamp files.  Remove unused files manually.

       Anacron uses up to two file descriptors for each	active	job.   It  may
       run out of descriptors if there are more	than about 125 active jobs (on
       normal kernels).

       Mail comments, suggestions and  bug  reports  to	 Sean  'Shaleh'	 Perry
       <shaleh@(debian.org|valinux.com)>.

AUTHOR
       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  is  currently	 maintained  by	 Sean  'Shaleh'	 Perry
       <shaleh@(debian.org|valinux.com)>.

Sean 'Shaleh' Perry		  2000-06-22			    ANACRON(8)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SIGNALS | NOTES | FILES | SEE ALSO | BUGS | AUTHOR

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