[TUHS] Command line options and complexity
Greg 'groggy' Lehey
grog at lemis.com
Fri Mar 13 11:02:06 AEST 2020
On Wednesday, 11 March 2020 at 23:34:46 -0400, Steve Nickolas wrote:
> On Thu, 12 Mar 2020, Greg 'groggy' Lehey wrote:
>> -S isn't POSIX. And to implement it without an option would mean
>> removing -h.
> -h is a gnuism, isn't it?
It might have originated there, but then I would expect it to be spelt
'--produce-human-readable-output'. I haven't been able to establish
from the FreeBSD sources or commit logs when it was introduced. It
would clearly have been a reimplementation.
> https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ls.html does
> specify the -S switch. That's POSIX, isn't it?
So it is! This was the first option that I wanted to add, back when I
still had practice wheels. I asked my mentor, and he said "not the
Unix way", so I let it be. Then Wes Peters came up with the idea, and
I thought he committed it, but it seems that it ultimately came from
Kostas Blekos in 2005, based on the same feature on NetBSD and
OpenBSD. I wonder when it made it to POSIX.
>> As I mentioned earlier, -t can't be done by a filter without
>> significantly modifying the timestamp output. That was my rationale
>> for the -D option, which allows sorting by an external filter.
> Honestly if the date format weren't standardized as it were, I would've
> standardized on "yyyy-mm-dd,mm:ss" - which wouldn't need special
> processing in order to pump into sort(1).
Yes, that was one of the possibilities I thought of. Another obvious
one was time_t, which is even easier to process. And then there's ISO
8601. That's why it didn't take me long to decide "do it *your* wayâ
with the -D option.
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