Re: [bug-mailutils] Is this a Bug? Readmsg Omits From Line

[Neil R. Ormos]

Sergey Poznyakoff wrote:
> Neil R. Ormos <address@hidden> wrote:

> > Nonetheless, I would observe that the elm
> > version of readmsg is quite useful for copying
> > verbatim one or more messages from one
> > mbox-format mailbox into another mbox-format
> > mailbox, using the -h option.  It would be
> > useful to have similar functionality in the GNU
> > Mailutils readmsg, regardless of which option
> > flag must be requested to access this
> > functionality, because eventually, maintenance
> > of elm will likely cease.

> I see. I will apply the 1st patch to CVS head, then.

> > On my test system (Debian Sarge), after the patch
> > you offered on 12 Feb 2007, the invocation

> >    readmsg -w 'From_ \' -f source.mbox 5 6 7 >destination.mbox

> From the shell's point of view, 'From_ \' is an
> error (the closing quote is missing), that's why
> I thought it was a typo and tried 'From_ '\'
> instead.

> Indeed, when using this form literally, I obtain
> the same results as you.  It is due to the fact
> that mailutils word splitter (argcv module)
> parses this string in two words: 'From_' and ''.
> The first one instructs readmsg to output From
> markers, the second one matches any headers (One
> can argue that it should not have removed the
> trailing \, but that's another story). You would
> get the same effect with any of the following
> (correct from the shells point of view) calls:

>  readmsg -w 'From_ ""'
>  readmsg -w "From_ ''"

Thank you for pointing this out.  This duplicates
the functionality of the elm readmsg -h option. I
should have discovered these on my own, but didn't
realize that the -w option would handle "" or ''
pairs specially.  (For what it's worth, elm
readmsg treats these quote pairs as header
patterns beginning with the quotes, rather than as
an empty string.)

Perhaps the man page for readmsg could include a
hint to users about how to duplicate the behavior
of the -h option of elm readmsg to extract
messages verbatim from mbox format mailboxes.  I'd
be happy to contribute some proposed language, but
I might need some help to produce a patch in the
proper format.

> > I have not seen documentation for readmsg that
> > specifies that the arguments to -w are treated as
> > "patterns",

> Well, this is a terminological issue, which can
> be argued, indeed.  In my understanding, they
> can be called "patterns" because they do not
> match the header names exactly, instead any
> header whose prefix matches is selected.

Thanks. I see what you mean now.  I was
erroneously interpreting "patterns" too narrowly
as meaning the kind of regular-expression pattern
matching present in AWK, etc.

> > so I wasn't aware that ! is intended
> > to be special.

> According to readmsg(1):

>  "A list entry may be preceded by an exclamation
>  point to suppress the header."

> Thus, ! is special. But this is the only mention
> of its special meaning in the docs. It does not
> specify how the matcher should behave when
> encountering "X !X" or "!X X".

> > I was looking at the info page and the (Debian)
   man page for readmsg.

> Yes, the above excerpt was taken from this
> manpage as well.

I wasn't clear enough in my prior message.  I
don't know which features of elm readmsg are
intended to carry over into GNU Mailutils readmsg.
I did see the "preceded by an exclamation point"
instruction in the readmsg(1) man page supplied by
elm 2.5.8., but not in any of the GNU Mailutils
documentation.  I looked at the info page
furnished with Mailutils 1.1 and the web man page
at:

  <http://www.gnu.org/software/mailutils/manual/html_node/readmsg.html>

If I should be looking elsewhere at something more
up-to-date, please let me know.

Thank you for your help and patience.

Best regards,

--Neil Ormos