anacron

[Derek Broughton]

Toby Kelsey wrote:

> Derek Broughton wrote:
> 
>> Anacron exists to ensure that scheduled jobs run _sometime_.  So it runs
>> at
>> boot _and then stops_.  It also runs at set times of day (specified by
>> cron) to execute the cron.*ly schedules.  If you want something to
>> _always_ run at an exact time, you put it in a crontab, if you want
>> something to always get run, even if your system isn't up when scheduled,
>> you use anacron.
> 
> Or better, use fcron, as has been suggested.

Not yet, but I'll probably get to the suggestion shortly :-)

A quick look at fcron makes me suspect that it isn't an adequate
substitute - whatever you use can't supercede cron, or gcrontab/kcron
become useless.
> 
>> "Description: a cron-like program that doesn't go by time" seems to be
> 
> Given the etymology and function of cron, it is a confused and
> self-contradictory description.  What is cron if not a "by time" program?

We're not discussing "cron", we're discussing "anacron", which explicitly
does NOT go by time.
> 
> The man page has a better summary "anacron - runs commands periodically"

Not particularly, since it led you to believe there'd be some periodicity.

> Clearly, when anacron is installed it _usurps_ the usual cron directories
> /etc/cron.*ly.  Yes you can still edit the crontab but for the more
> user-friendly directories it's not a supplement but is installed as a
> replacement.  So both end-users and Ubuntu-designers are confused by its
> name into thinking it's a replacement for cron.  

I'm sure you're not the first - but the only one I've seen.

> It should be called 
> something different like 'periodic' and use its own directories.

Absolutely not!!!!  How on earth would I get it to run the cron jobs that
have been missed while my laptop was off?  You're missing the point of
anacron.
-- 
derek