Re: Question of sort(1)

[Paul Goyette <paul%whooppee.com@localhost>]

On Sun, 29 May 2016, Robert Elz wrote:

>    Date:        Sat, 28 May 2016 21:02:58 +0800 (PHT)
>    From:        Paul Goyette <paul%whooppee.com@localhost>
>    Message-ID:  <Pine.NEB.4.64.1605282053260.5162%pokey.whooppee.com@localhost>
>
>  | and execute 'sort -t / -k 1 < IN' (field separator is /, sort on first
>  | field) I get (what I believe to be) incorrect results:
>
> No, what you get is correct.
>
>  |  	# sort -k1 -t / < IN
>
> -k1 means from the start of field 1 to end of line.   From the man page:
>
>     Fields are specified by the -k field1[,field2] argument.  A missing
>     field2 argument defaults to the end of a line.
>
> Posix says the same, in slightly different words...
>
> 	-k field_start[type][,field_end[type]]
>
> 	shall define a key [...]
> 	A missing field_end shall mean the last character of the line.
>
> '-' < '/' hence a-0/y < a/z
>
>  | Interestingly, it works as expected if the field delimiter is set to a
>  | space (and the input data updated accordingly):
>
> That's because ' ' < '-'.
>
>  | So, is this a bug?  Or is this working-as-designed (and therefore my
>  | expectations need to be reset)?
>
> The latter.   For what you want, use -k1,1
>
> 	sort -t/ -k1,1 /tmp/F
> 	a/z
> 	a-0/y
> 	a-1/x


Ah, thanks!  -k1,1 does indeed do what I would expect!



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