On 28/09/2023 11:11, Jorge Stolfi wrote:
The full documentation of sort explains that numeric sorting (as in
"sort -n") accepts a leading "-" sign, decimal points, thousands
separators, etc, but does not accept an explicit "+" sign. Values with
explicit "+" are treated as numeric 0 and ties are broken by alpha sort.

However, the manpage only says that "-n" "compares according to string
numerical value" -- and one would expect the numerical value of "+100"
to be 100, not zero.

It took me an hour to figure out that my "sort -n" was failing because
of this "feature".  Surely many users have wasted time too, or worse.
So please either

1) explain precisely IN THE MANPAGE what is a valid number;

2) make numeric sort accept a leading "+", as users would expect;

3) make numeric sort abort with an error message if any field that is
supposed to be sorted numerically is not a valid number.

I think the best solution for users would be to implement all three of

Thank you, and all the best

Note the --debug option really helps with all this:

  $ printf '%s\n' '+4' ' 5' '-1,2.3' | sort -s -n --debug
  sort: note numbers use ‘.’ as a decimal point in this locale
  ^ no match for key

In saying that, sorting numbers is such a common use case,
it's probably worth adding an extra couple of lines to the man page.
I think I'll apply the following later:

  -n, --numeric-sort          compare according to string numerical value.
                                leading blanks, negative sign, decimal point,
                                and thousands separators are supported.


Reply via email to