Re: [patch] cat -n bug from 33 years ago

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sat, 18 Nov 2023 14:24:48 -0500 (EST)
    From:        Mouse <mouse%Rodents-Montreal.ORG@localhost>
    Message-ID:  <202311181924.OAA10649%Stone.Rodents-Montreal.ORG@localhost>

  | The manual is semi-silent on it.  It's not specifically described, but
  | -n is documented as numbering "the output lines", which I think
  | indicates the numbering should continue.

This is a difficult one to make a decision about.

In the original BSD cat, when -n (and a whole bunch of other options
were added) in Oct 1980, -n worked numbering the output lines (regardless
of the input file which generated them).   That is, it had "lno" as a global
var, which (naturally) started at 0, and was incremented when each line was
written - never reset.

In Mar 1989 a whole new implementation of cat replaced the original, in that
one things switched to the way that are now (and remained that way until the
end of the CSRG distributions) - with "line" being a local var, init'd to 0,
in the function used to output a single file, so the output line numbering
restarts for each input file.

So, if one were to simply consider the history, neither one is automatically
the intended behaviour.

Whether the changed behaviour of the 1989 version was deliberate or not,
I have no idea (the commit messages in the SCCS files tended to be a lot
more terse than we often see today).

kre