Re: "sort -nu" treatment of "0" & empty lines

[Jim Meyering]

"Ulrich Hermisson" <address@hidden> wrote:

> Hello,
>
> the following behaviour of "sort -nu" needs not necessarily be considered a
> bug:
>
> $ echo ",2,0,1,-2,3,-4" | tr "," "\n" | sort -nu
> -4
> -2
>
> 1
> 2
> 3

Thanks for the report.
POSIX requires sort, with -n or `-kM,Nn', to interpret an empty field as 0.
The documentation (info sort) already says that an empty field is valid
but doesn't specify how it's interpreted.

I've just added a sentence saying that.
Here's the new description:

`--numeric-sort'
     Sort numerically: the number begins each line; specifically, it
     consists of optional blanks, an optional `-' sign, and zero or more
     digits possibly separated by thousands separators, optionally
     followed by a decimal-point character and zero or more digits.  A
     string of zero digits is interpreted as `0'.  The `LC_NUMERIC'
     locale specifies the decimal-point character and thousands
     separator.