GNU bug report logs - #10755
stat: Please add directive to display size on disk (%S)

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

From: Filipus Klutiero <chealer <at> gmail.com>
To: bug-coreutils <at> gnu.org
Subject: stat: Please add directive to display size on disk
Date: Tue, 07 Feb 2012 15:10:51 -0500

The other day I tried figuring out how much disk space a small file 
took. I used stat, but I only realized today that stat does not provide 
that information directly, as explained by Eric Blake and Pádraig Brady 
in http://debbugs.gnu.org/cgi/bugreport.cgi?bug=10561

This information is provided indirectly by %b and %B. Multiplying the 2 
should give the size on disk. Example:

stat -c 'allocated-space=%B*%b apparent-size=%s' $file

Currently, this information can be obtained from du:

$ stat -c '%s' /etc/phpmyadmin/htpasswd.setup
54
chealer <at> vinci:~$ du -h /etc/phpmyadmin/htpasswd.setup
4,0K    /etc/phpmyadmin/htpasswd.setup
chealer <at> vinci:~$

However, it would be quite useful if stat could be used to display 
simultaneously a file's real size and size on disk.


Eric Blake suggested this directive to be %S. For the description, he 
suggested:

%S  Allocated size (same as %b * %B)

I would like to aim for clarity, as these various statistics can be 
confusing. I suggest to use the name "Size on disk". I also suggested 
the following:

Size occupied when including slack space
Size of the clusters occupied

I suggest the following synthesis:

Allocated size (space allocated on the storage device, same as %b * %B). 
This is the size of the allocated clusters, which includes slack space.

Message #8 received at 10755 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Filipus Klutiero <chealer <at> gmail.com>
Cc: 10755 <at> debbugs.gnu.org
Subject: Re: bug#10755: stat: Please add directive to display size on disk
Date: Tue, 07 Feb 2012 12:54:44 -0800

On 02/07/2012 12:10 PM, Filipus Klutiero wrote:
> Size on disk

We don't know it's a disk drive; it might be
any storage device that contain a file system.
Perhaps a better shorthand string would be "Allocation"?
That's even shorter, and it conveys what's going on.

Message #11 received at 10755 <at> debbugs.gnu.org (full text, mbox):

From: Filipus Klutiero <chealer <at> gmail.com>
To: 10755 <at> debbugs.gnu.org
Subject: Re: bug#10755: stat: Please add directive to display size on disk
Date: Tue, 07 Feb 2012 17:35:27 -0500

On 2012-02-07 15:54, Paul Eggert wrote:
> On 02/07/2012 12:10 PM, Filipus Klutiero wrote:
>> Size on disk
> We don't know it's a disk drive; it might be
> any storage device that contain a file system.

I agree. I see an advantage in using the term "Size on disk": it is well 
known from Windows ( 
http://technet.microsoft.com/en-us/magazine/hh148159.aspx ). But indeed, 
it does not always apply. It could be mentioned in a parenthesis and/or 
in quotes nevertheless to facilitate search.
> Perhaps a better shorthand string would be "Allocation"?
> That's even shorter, and it conveys what's going on.

Oh, good question. We currently have:

> Size: 54              Blocks: 8          IO Block: 4096

If we want to display the allocated size too, "Size" for "real"(?) size 
becomes clearly ambiguous. How about having a line for size? Something like

> Size    Real: 54    Allocated: 4096

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