This might be relevant:

uniq: missing option -W / --check-fields=N
http://lists.gnu.org/archive/html/bug-coreutils/2006-06/msg00168.html



Steve


On Sat, Apr 3, 2010 at 14:39, Raphael Clifford <drraph@gmail.com> wrote:

> Please excuse the cross-post but I have been told this is the
> appropriate place to place a feature request.
>
> Is it possible to make a feature request for uniq to add the "-k"
> option to specify
> fields?  Interestingly uniq already has such things as
>
> -f, --skip-fields=N
>             avoid comparing the first N fields
> and
>
>  -s, --skip-chars=N
>             avoid comparing the first N characters
>
> but no explicit option to specify which fields should be considered
> when doing the comparison.  This would be very useful, for example,
> when removing duplicates from time series data (where you are only
> worried about consecutive duplicates on certain fields).  The awk
> equivalent would be something like
>
> awk '$2$3$4$5 !=  p; {p=$2$3$4$5}'
>
> for using fields 2 to 5 as comparators.
>
> Raphael
>
> P.S. http://www.opengroup.org/onlinepubs/9699919799/utilities/uniq.html
> is the posix specification for uniq if that is of any interest.
> Curiously it says nothing about which duplicate line to keep when you
> don't consider all fields in the comparison.
>
>
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