Re: --version output and license specifications

[Bob Proulx]

Paul Eggert previously wrote:
> "sort --version" could output something like this, say:
> 
>   sort (GNU coreutils) 6.2
>   Copyright (C) 2006 Free Software Foundation, Inc.
>   License: GPL v2 <http://www.gnu.org/licenses/gpl.html>.
>   This is free software.  There is NO WARRANTY, to the extent
>   permitted by law.
Karl Berry wrote:
> GNU GPL v2+ ... the + is very important.

Paul Eggert wrote:
> For GNU licenses, it might be simpler if the --version output merely
> referred to <http://gnu.org/licenses>, as that will make the output
> shorter and the instructions for maintainers simpler.  I suspect that
> this URL won't change more often than the FSF changes physical mail
> addresses, so it'll be good enough in practice.  (In this URL I
> dropped the "www."  and the trailing "/" in the interest of brevity.)

That saves only five characters over the more strictly exact form and
only a few more over the much more strictly exact form.

Here are the proposals as I saw them go by, splitting the last because
it changes two things at once and I want to make them available for
discussion separately.

  (1) http://www.gnu.org/licenses/gpl.html
  (2) http://www.gnu.org/licenses/
  (3) http://www.gnu.org/licenses
  (4) http://gnu.org/licenses

Number 1 is of course fully specified and would assume nothing.  I
think in this case this is most desirable.

Number 2 assumes that the web server will automatically convert the
address.  It would be a directory listing or it could be index.html or
another file that the web server is configured to do in the default
case.  IIRC this is fully allowed by the web standards.  I think this
would be okay when the page is the default page, such as index.html.
But not okay when it is not the default page.  In this case these two
URLs refer to different locations.  Number 1 refers to gpl.html and
number 2 refers to index.html.

Number 3 leaves more work for both the web server and client.  The web
server must redirect the user to the http://www.gnu.org/licenses/ and
then the client must retry.  Upon retry this case becomes number 2.  I
think requiring the redirection and retry is undesirable.  With the
redirection we include all of the issues of number 2.

Number 4 changes hostnames from the specified web server IP to the
domain default IP.  Currently this is the same IP address.  There is
no reason to believe that this would not be desirable to split out
into separate IP addresses at some time in the future.  (Sure there
are a lot of technical solutions such as port forwarding but let's
keep things simple.)  It would be unfortunate to prevent a small
technical change such as creating a separate www.gnu.org IP from
gnu.org IP for a legal reason of needing to maintain a web presence on
the default domain address.  Currently there is no such requirement
that I know of and I would think it undesirable to create it.

All things being equal I would select number 1 and use the fully
qualified URL address.

Bob