bug#9939: Problems with the SIZE description in man pages for <ls> and <du>

[Paul Eggert]

On 11/02/11 03:40, abdallah clark wrote:

> the units are not
> consistent with the ISO/SI units-- K and M are in units of 1000, not
> 1024, because they are part of the metric system, not the binary
> system.

coreutils is supporting three notations here: SI-ish,
IEC 60027-2 / ISO/IEC 80000-13:2008, and traditional Unix.
So:

  MB means 1000*1000 bytes.  This is like SI, except SI doesn't have "B".
  MiB means 1024*1024 bytes.  This is IEC 60027-2 and ISO/IEC 80000-13:2008.
  M means MiB.  This is traditional Unix.

See <http://en.wikipedia.org/wiki/Binary_prefix> for more info.
(coreutils cannot use plain SI, since SI doesn't specify
an abbreviation for "byte".)

> it is just too awkwardly
> written to be understood on the first reading.

Suggestions for improved wording are welcome.  We'd like it to be
short, of course.
        
> Also, the statement "Mandatory arguments to long options are mandatory
> for short options too." puzzles me

Yes, I don't like that sentence either.  Suggestions for
improvement are welcome here, too.  Maybe we should just get
rid of it?  I expect it causes more confusion than it cures.