Anacron stands for
anachronistic.
One of cron's biggest
weaknesses is that it assumes that your server or computer is always on. If
your machine is off and you have a task scheduled during that time, the task
will never run.
This is a serious
problem with systems that cannot be guaranteed to be on at any given time. Due
to this scenario, a tool called "anacron" was developed.
#vi /etc/anacrontab
The first
column specifies how often the command should be run.
The second
column is the delay to use before executing the commands.
For example, the
first line runs every day, five minutes after anacron is called:
1
5 cron.daily nice run-parts --report /etc/cron.daily
The following line is
run weekly (every 7 days), ten minutes after anacron is called:
7
10 cron.weekly nice run-parts --report /etc/cron.weekly
The third column contains the name
that the job will be known as in the anacron's messages and log files. The
fourth field is the actual command that is run.
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