GNU bug report logs - #25560
Alphabetic Character Following date -d

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Owen Leibman <eclipsechasers2 <at> yahoo.com>
Subject: bug#25560: closed (Re: bug#25560: Alphabetic Character Following
 date -d)
Date: Sat, 28 Jan 2017 10:37:02 +0000

[Message part 1 (text/plain, inline)]

Your bug report

#25560: Alphabetic Character Following date -d

which was filed against the coreutils package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 25560 <at> debbugs.gnu.org.

-- 
25560: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=25560
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Owen Leibman <eclipsechasers2 <at> yahoo.com>, 25560-done <at> debbugs.gnu.org
Subject: Re: bug#25560: Alphabetic Character Following date -d
Date: Sat, 28 Jan 2017 02:35:59 -0800

Owen Leibman wrote:
> Is the date command behaving as it should for all these examples?

Those letters are military time zone abbreviations, so yes.

[Message part 3 (message/rfc822, inline)]

From: Owen Leibman <eclipsechasers2 <at> yahoo.com>
To: "bug-coreutils <at> gnu.org" <bug-coreutils <at> gnu.org>
Subject: Alphabetic Character Following date -d
Date: Sat, 28 Jan 2017 06:15:58 +0000 (UTC)

Testing a script to see how it handled invalid data, I had it execute the command:
date -d "x023-04-05 01:00"
Somewhat surprisingly, this was not treated as an error. The response was:
Tue Apr  4 06:07:02 LMT 0023

This happened on a Ubuntu system using coreutils-8.25.
However, I was not able to duplicate it on a Cygwin system using coreutils 8.26,
Where the date was flagged as invalid.
So, at a guess, this was a bug that was fixed in 8.26.

But, not so fast - the following commands give identical surprising results with both versions
(for convenience, I set my time zone to UTC before issuing these commands):

date -d a
Sat, Jan 28, 2017  1:00:00 AM

I searched the man and info pages in vain for how the command might be interpreting "a" here.
If there is some place where this is documented and I just missed it, please let me know.
In the meantime, I'll continue.

I tried other letters - "b" through "i" each advanced the displayed time by 1 hour (so "i" was 9:00).
Upper- and lower-case were treated the same.

At "j", I had a surprise:

date -d j
date: invalid date ‘j’

But then I was equally surprised by "k":

date -d k
Sat, Jan 28, 2017 10:00:00 AM

It seems to have picked up where the sequence was broken.
Continuing, "l" advanced to 11:00, and "m" to 12:00 (PM - presumably noon).
Another surprise came with "n":

date -d n
Fri, Jan 27, 2017 11:00:00 PM

From that point, the result marches backwards by an hour each time until "x" reaches 1:00 p.m.
Then "y" matches the output for "m". And "z":

date -d z
Sat, Jan 28, 2017 12:00:00 AM

And, having run out of letters, my test was complete.

Is the date command behaving as it should for all these examples?

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.