GNU bug report logs - #35078
Possible bug in the date command, to do with %p

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 35078 in the body.
You can then email your comments to 35078 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Nicholas Joll <najoll <at> posteo.net>
To: bug-coreutils <at> gnu.org
Subject: Possible bug in the date command, to do with %p
Date: Tue, 2 Apr 2019 09:14:45 +0100

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

Package: date
Version: GNU coreutils 8.28

The manual for 'date' includes this:

       %p     locale's equivalent of either AM or PM; blank if not known

       %P     like %p, but lower case

But on my system:

     $  date +%p
    am
    $  date +%P
    am

That is: it seems impossible to get a capitalised 'AM' or 'PM'.

Might this be a problem with my locale? Here is how my locale is set:

    $  locale
    LANG=en_GB.UTF-8
    LANGUAGE=en_GB:en
    LC_CTYPE=en_GB.UTF-8
    LC_NUMERIC=en_GB.UTF-8
    LC_TIME=en_GB.UTF-8
    LC_COLLATE="en_GB.UTF-8"
    LC_MONETARY=en_GB.UTF-8
    LC_MESSAGES="en_GB.UTF-8"
    LC_PAPER=en_GB.UTF-8
    LC_NAME=en_GB.UTF-8
    LC_ADDRESS=en_GB.UTF-8
    LC_TELEPHONE=en_GB.UTF-8
    LC_MEASUREMENT=en_GB.UTF-8
    LC_IDENTIFICATION=en_GB.UTF-8
    LC_ALL=


My OS: (GNU-)Linux Mint 19.1 x64 Cinnamon

Yours,


Nicholas

[0x63EC0B0B39DEE1CD.asc (application/pgp-keys, attachment)]

Message #8 received at 35078 <at> debbugs.gnu.org (full text, mbox):

From: Assaf Gordon <assafgordon <at> gmail.com>
To: Nicholas Joll <najoll <at> posteo.net>, 35078 <at> debbugs.gnu.org
Subject: Re: bug#35078: Possible bug in the date command, to do with %p
Date: Tue, 2 Apr 2019 10:48:45 -0600

tags 35078 notabug
close 35078
stop

Hello,

On 2019-04-02 2:14 a.m., Nicholas Joll wrote:
> The manual for 'date' includes this:
>         %p     locale's equivalent of either AM or PM; blank if not known
>         %P     like %p, but lower case
> 
> But on my system:
> 
>       $  date +%p
>      am
>      $  date +%P
>      am
> 
> That is: it seems impossible to get a capitalised 'AM' or 'PM'.
> 
> Might this be a problem with my locale? Here is how my locale is set:
> 
>      $  locale
>      LANG=en_GB.UTF-8

Exactly as you suspected: it is due to your locale.

Note the wording:
  "locale's *equivalent* of either AM or PM"
So not the exact strings AM or PM, but what your locate uses.

In C/POSIX, these are indeed upper/lower case:

  $ LC_ALL=C date +"%p %P"
  AM am

Same for Canada:

  $ LC_ALL=en_CA.UTF-8 date +"%p %P"
  AM am

But not for Great Britain:

  $ LC_ALL=en_GB.UTF-8 date +"%p %P"
  am am

Also note that these are blank in many other locales:

  $ LC_ALL=ru_RU.utf8 date +"=%p=%P="
  ===



I'm making this as "not a bug", but discussion can continue by
replying to this thread.

-assaf

Message #15 received at 35078 <at> debbugs.gnu.org (full text, mbox):

From: Nicholas Joll <najoll <at> posteo.net>
To: Assaf Gordon <assafgordon <at> gmail.com>, 35078 <at> debbugs.gnu.org
Subject: Re: bug#35078: Possible bug in the date command, to do with %p
Date: Tue, 2 Apr 2019 21:22:18 +0100

Dear Assaf (and all)

> I'm making this as "not a bug", but discussion can continue by
replying to this thread.
> -assaf

Thank you Assaf for your lucid explanation and for your invitation to
discussion.

I imagine that this matter arises fairly frequently. For, the behaviour
here is not what one expects (at least not what the
less-than-fully-informed user expects).

One might think there is no real problem: though lowercase 'am'/'pm'
looks somewhat odd, and is not what the user expects when using '%P', it
is easy programmatically to convert lowercase to uppercase. Yet, some
people will use the program 'Conky' to display the time, and (to my
knowledge) Conky cannot do the string conversion.

I have two suggestions. (1) Amend the manual such that it says something
like the following.

    %P     like %p, but lower case (or uppercase if uppercase is all
that the locale provides)

(2) Add (and document) a new option that works thusly:

    %PP     locale's implementation of AM/PM (or blank if the locale has
no such implementation), forced into uppercase

1 is somewhat important. The conjunction of 1 and 2 would be ideal. Or
so it seems to me.

Nicholas

Message #18 received at 35078 <at> debbugs.gnu.org (full text, mbox):

From: Eric Blake <eblake <at> redhat.com>
To: Nicholas Joll <najoll <at> posteo.net>, Assaf Gordon <assafgordon <at> gmail.com>,
 35078 <at> debbugs.gnu.org
Subject: Re: bug#35078: Possible bug in the date command, to do with %p
Date: Tue, 2 Apr 2019 22:08:40 -0500

On 4/2/19 3:22 PM, Nicholas Joll wrote:

> I have two suggestions. (1) Amend the manual such that it says something
> like the following.
> 
>     %P     like %p, but lower case (or uppercase if uppercase is all
> that the locale provides)
> 
> (2) Add (and document) a new option that works thusly:
> 
>     %PP     locale's implementation of AM/PM (or blank if the locale has
> no such implementation), forced into uppercase

We can't spell it %PP (that would be parsed as "%P" "P"), but we could
take a leaf from %:z (and even %:::z) if we wanted to use : as a flag to
force particular capitalizations.  Of course, even toupper()/tolower()
are locale-dependent, so it's still hard to say what could really be
forced if we added particular variants for overriding a locale's
preferred case.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

Message #23 received at 35078 <at> debbugs.gnu.org (full text, mbox):

From: Nicholas Joll <najoll <at> posteo.net>
To: eblake <at> redhat.com, assafgordon <at> gmail.com, 35078 <at> debbugs.gnu.org
Subject: Re: bug#35078: Possible bug in the date command, to do with %p
Date: Wed, 3 Apr 2019 21:08:58 +0100

Dear all

    The following relevant thing has been brought to my attention (by a
Conky developer):

     $  man strftime | grep Convert

            ^      Convert alphabetic characters in result string to
uppercase.

i.e., strftime, which is, I believe, a C function included in the C
'time' library, has an option (which one can use in Conky, actually) to
convert output to all uppercase - thus achieving what I desired. 'Date'
could implement something similar.

Yours

Nicholas

On 03/04/2019 04:08, Eric Blake wrote:
> On 4/2/19 3:22 PM, Nicholas Joll wrote:
>
>> I have two suggestions. (1) Amend the manual such that it says something
>> like the following.
>>
>>     %P     like %p, but lower case (or uppercase if uppercase is all
>> that the locale provides)
>>
>> (2) Add (and document) a new option that works thusly:
>>
>>     %PP     locale's implementation of AM/PM (or blank if the locale has
>> no such implementation), forced into uppercase
> We can't spell it %PP (that would be parsed as "%P" "P"), but we could
> take a leaf from %:z (and even %:::z) if we wanted to use : as a flag to
> force particular capitalizations.  Of course, even toupper()/tolower()
> are locale-dependent, so it's still hard to say what could really be
> forced if we added particular variants for overriding a locale's
> preferred case.
>

Previous Next

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