[re-adding the list, with permission] On 10/11/2013 01:53 PM, Reed Underwood wrote: >> For example, The Julian Date for 00:30:00.0 January 1, 2013 is >> 2456293.520833. >> >> If the astronomical term is what you want, then maybe you really do have >> a format that cannot be expressed in any existing notation, and maybe it >> really is worth burning a % notation. But how common is the >> Astronomical Julian Date in shell programming? >> > > I instinctively turned to 'date' for the full Julian date for astronomical > purposes, > but I concede that this is not an incredibly common use case. I thought I'd > pitch it to see if there's any interest. If it's too much of an edge case, > no problem. I just noticed there's no '%J' and thought it might be alright > to roll it in, figuring that I'm likely not the *only* person who's ever > wondered if 'date' could do this (but maybe I am!).
It might be worth asking on libc-al...@gnu.org if the glibc folks are interested in an extension for Julian date, as the date(1) command heavily copies from glibc's strftime(3). If we burn a letter in coreutils without their consent, and they later choose to give that letter a different meaning, then we're stuck - so we'd need to coordinate the addition across both projects if there is enough consensus that it is worth adding. > > Definitely, the '%j' form gives you the day of the year, which is likely > more commonly used (though I'm not sure in what context). At this point, I'm guessing that there's probably not enough demand to warrant adding astronimical Julian Date to the general-purpose date command, but it may also help to collect a few more opinions from others before giving up on the attempt. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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