Re: uniq: missing option -W / --check-fields=N

[Pádraig Brady]

Jim Meyering wrote:
> 
> Hi Matt,
> 
> I'm glad you're willing to work on this.
> It's an often-requested feature.
> Unfortunately, the Debian -W patch was not acceptable.
> It did not allow the same flexibility that sort does in
> selecting keys.  To provide that, GNU uniq will eventually
> accept at least the following options, just as sort does:
> 
>   -k, --key=POS1[,POS2]     start a key at POS1, end it at POS2 (origin 1)
>   -t, --field-separator=SEP  use SEP instead of non-blank to blank transition
>   -z, --zero-terminated     end lines with 0 byte, not newline
> 
> and even most, if not all, of these (for flexibility/interoperability
> with sort, as well as to ease code sharing between uniq and sort):
> 
>   -b, --ignore-leading-blanks  ignore leading blanks
>   -d, --dictionary-order      consider only blanks and alphanumeric characters
>   -i, --ignore-nonprinting    consider only printable characters

agreed

>   -f, --ignore-case           fold lower case to upper case characters

It has this already. See below.

>   -g, --general-numeric-sort  compare according to general numerical value
>   -M, --month-sort            compare (unknown) < `JAN' < ... < `DEC'
>   -n, --numeric-sort          compare according to string numerical value
>   -r, --reverse               reverse the result of comparisons

These 4 deal with specific order which I don't think uniq should worry about?

uniq can be efficient and assume LANG=C always as
it need only care if adjacent items match or not.
Assuming LANG=C may be an issue for --ignore-case though?
However I notice v5.2.1 at least only seems to handle ascii:

$ LANG=ga_IE.utf8 uniq -i < Pádraig
Pádraig
PÁdraig