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RedHat 9 (Linux i386) - man page for anacron (redhat section 8)

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
       /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 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 timestamp file for that
       job, so it can know when to execute it again.  Only the date is used for the time calcula-
       tions.  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 background 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 completely 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 priority 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 executed 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  any-
	      thing.

       -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 /etc/anacrontab  file.   This
	      options implies -s.

       -d     Don't fork to the background.  In this mode, Anacron will output informational mes-
	      sages 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 accomplished by setting the TZ environment variable,
       or by installing a /usr/lib/zoneinfo/localtime file.  See tzset(3) for more information.

FILES
       /etc/anacrontab
	      Contains specifications of jobs.	See anacrontab(5) for a complete 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  descrip-
       tors 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|val-
       inux.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|val-
       inux.com)>.

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


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