Re: coreutils uniq -d -u does not conform to POSIX

[Paul Eggert]

address@hidden writes:

> > But -u -d is clearly valid, since POSIX says it's valid.
> 
> have you a link to the POSIX docs?

http://www.opengroup.org/onlinepubs/007904975/utilities/uniq.html

In order to understand that page fully, you need to read a lot of the
other part of the spec.  But for this particular issue the page is
pretty self-explanatory.

> > -u Discard the first repeated line.
> 
> This isn't as clear to me as "only print unique lines"

Perhaps not, but "only print unique lines" isn't correct.

> > Under this convention, -D is not incompatible with -d or with -u.
> 
> agreed, but redundant => should warn user as I summarised above

I don't see why a warning would be useful.  GNU utilities often accept
redundant options without complaint.

> All this is too complicated. IMHO uniq should just have
> 
>      --group={min,max,num_to_show,delimter}

That's simpler?  I dunno....