OT: Cron question
Jakob Østergaard
jakob at unthought.net
Wed Feb 13 17:17:43 PST 2002
On Wed, Feb 13, 2002 at 07:16:03PM -0500, Robert G. Brown wrote:
...
>
> Dunno. Perhaps it is (from man 5 crontab, emphasis added):
>
> ...and when AT LEAST one of the two day fields (day of month, OR day of
> week) match...
Yep - someone else just pointed this out to me in private mail: I somehow
managed to read the man-page 10 times without seeing the following:
Note: The day of a command's execution can be specified by
two fields -- day of month, and day of week. If both
fields are restricted (ie, aren't *), the command will be
run when either field matches the current time. For exam
ple,
``30 4 1,15 * 5'' would cause a command to be run at 4:30
am on the 1st and 15th of each month, plus every Friday.
Duh !
> This seems like it would run every friday, right, since it matches day
> of week 5, regardless of whether or not it matches your day of month
> range. It would need an "and" operator to do what you want.
<rant>
Yep. The same "and" operator which is present between all other fields,
*except* for the last one.... I wonder what the logic behind this last
special rule would be...
</rant>
On second thought, I guess I should consider such peculiarities "charming"
rather than annoying - hey, if it was easy, it wouldn't be fun. ;)
>
> In the face of it not working (and I don't see any simple cron recipe
> that will do what you want) there are simple and obvious solutions.
> Instead of running either job A or job B, run a simple script that runs
> every Friday, looks at the date, and then runs A or B.
Yep - that looks like it will be the way to go.
>
> Making cron work at this level of detail may be possible. May not.
> Either way, I know how /bin/sh (or perl) and date and so forth work and
> they add negligible overhead to this kind of chore. There are always
> lots of ways to do things. Pick the easiest.
Yup, time to script...
Thanks a lot,
--
................................................................
: jakob at unthought.net : And I see the elder races, :
:.........................: putrid forms of man :
: Jakob Østergaard : See him rise and claim the earth, :
: OZ9ABN : his downfall is at hand. :
:.........................:............{Konkhra}...............:
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