Linux in a Nutshell, Fifth Edition

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Linux

Commands

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Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

anacron

anacron [options] [job]

System administration command. Normally started in a system

startup file. Execute commands periodically. By default, anacron

reads a list of jobs from a configuration file, /etc/anacrontab. The

file consists of shell variables to use when running commands,

followed by a list of tasks to run. Each task specifies how often in

days it should be run, a delay in minutes to wait before running the

task, a unique job identifier used to store a timestamp, and the

shell command to execute. Timestamps for the last run of each task

are stored in the /var/spool/anacron file. For each task, anacron

compares the stored timestamp against the current time. If the

command has not been executed within the specified frequency,

the command is run. Upon completion, anacron records the new

date in the timestamp file. Limit anacron to a specified task by

providing the task’s unique job identifier on the command line.

The anacron command is often used to support the cron daemon

on systems that do not run continuously.

Options

-d Run in foreground rather than as a background process. Send

messages to standard error.

-f Run tasks ignoring timestamps.

-h Print help message, then exit.

-n Run tasks now, ignoring delay specifications.

-q Suppress messages to standard ...