[CentOS] lunar notation in crontab

Alice Wonder
Sun, 06 Dec 2015 10:25:53 -0000

On 12/06/2015 02:23 AM, ken wrote:
> Crontab offers many refined facilities for Western calendaring, but none
> for traditional Eastern-- lunar-- designations.  So for example, if one
> wants specify regular occurring events on full moons or on new moons,
> there is no way to do this.  Emacs (a text processor!?) accomplishes
> this.  The math for calculating lunar calendaring is already available;
> mathematical functions are already available for simple downloading and
> so would need simply integration into crond.
>
> User settings in crontab would make most sense designated in the 'day
of
> month' field with keyword either 'full' or 'new'
(abbreviated with 'f'
> or 'n') prepended to a signed integer number of days (N * 24
hours).
> I.e., "new+5" would specify '5 days after the new moon';
"full-1" would
> specify "24 hours prior to the full moon"; "new+0",
"new-0" and "new"
> would all mean the same: "the moment of the new moon".
>
> I suppose that alternate syntaxes could be more refined, including hours
> and minutes before/after new/full, so possibly useful, but then also
> more complex.  Alternate and more refined time periods would be a
> question for developers.

This could be very useful in biology where a lot of cycles are lunar based.