bug#33371: RFC: option for numeric sort: ignore-non-numeric characters

[Erik Auerswald]

Hi,

On 11/19/18 02:08, L A Walsh wrote:
> On 11/14/2018 12:27 AM, Erik Auerswald wrote:
> > On Tue, Nov 13, 2018 at 06:32:55PM -0800, L A Walsh wrote:
> > > I have a bunch of files numbered from 1-over 2000 without leading zeros
> > > (think rfc's)...
> > > They have names with a non-numeric prefix & suffix around the number.
> >
> > Are prefix and suffix constant? RFC files are usually named rfc${NR}.txt.
> >
> > > It would be nice if sort had the option to ignore non-numeric
> > > data and only sort on the numeric data in the 'lines'/'files'.
> >
> > Perhaps --version-sort could work for you?
> > [...]
> the 'sort -V' works by itself, works.
> [...]
> > > Or is there an options for this already, and my manpage out of date?
> >
> > AFAIK not exactly.
> > [...]
>      "-V" seems like it might be sufficient, but I doubt most
> non-computer types would know that -V would sort multiple numeric fields
> separated by invariant non-numeric characters in a numeric fashion
> (or would even know how a version sort is the other sorts).

As far as I remember, the definition of --version-sort is to follow the 
Debian GNU/Linux package version sorting rules. Those are based on 
numbers surrounded by text, but several characters have special meaning 
(e.g. '~' sorts before everything else, even before the empty string). 
Thus this is _not_ a "natural sort," but quite specific and potentially 
surprising.

$ printf -- 'foo\nbar\nfoo-bar\nfoo~bar\n' | sort --version-sort
bar
foo~bar
foo
foo-bar

> Given how well read docs are these days, almost need a literal definition
> of 'version sort' besides just calling it a 'version sort' (which we
> must admit, is 'jargon').

I think is worse than jargon, because it is specific to one kind of 
version numbering scheme.

> Along the lines of:
>
>     --version-sort |  -V       Sees inputs as a mix of numeric and 
> alphabetic (or "identifier")
>        fields, where the numeric fields are sorted naturally, and alpha
>        fields sorted alphabetically.  Fields may have separators like
>        '.', '_', or '-',  sometimes constrained by a specific computer
>        language, or may have no separator at all between numeric and
>        alpha fields.  This is type of sort is often called a       
> "version sort" in the computer field.

Thus I am not sure about your suggestion above. :-/

> ???  I listed 'version sort' at the end, as the equivalence so those who 
> tend
> to skip and read initial parts of lines/paragraphs would not just see 
> "version sort" and gloss over the rest, inserting their own equivalence
> for the definition -- especially likely w/"version-sort" being the long 
> form
> of the switch.

I like that strategy. :-)

Thanks,
Erik