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X-Authentication-Warning:	slinky.cs.nyu.edu: pechtcha owned process doing -bs
Date:	Tue, 22 Apr 2003 23:18:54 -0400 (EDT)
From:	Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To:	cygwin AT cygwin DOT com
To:	"Pierre A. Humblet" <pierre DOT humblet AT ieee DOT org>
cc:	cygwin AT cygwin DOT com
Subject:	Re: Erroneous line endings (cat,gawk,text mount)
In-Reply-To:	<20030423015254.GA38081907@hpn5170x>
Message-ID:	<Pine.GSO.4.44.0304222315020.19398-100000@slinky.cs.nyu.edu>
Importance:	Normal
MIME-Version:	1.0

On Tue, 22 Apr 2003, Pierre A. Humblet wrote:

> On Tue, Apr 22, 2003 at 07:54:17PM -0400, Igor Pechtchanski wrote:
> > On Tue, 22 Apr 2003, Pierre A. Humblet wrote:
> >
> > > On Tue, Apr 22, 2003 at 10:54:41PM +0100, Peter S Tillier wrote:
> > > > Replying to Igor Pechtchanski who wrote:
> > > >
> > > > > Also, "cat" will not translate line endings or anything at all --
> > > > > it's just a character-by-character copy of stdin to stdout.
> > > >
> > > > Fair enough (and what I expect it to be) thanks for the clarification.
> > >
> > > Igor, how do you explain the following behavior?
> > > ~: od -c
> > > abc
> > > 0000000   a   b   c  \n
> > > 0000004
> > > ~: cat | od -c
> > > abc
> > > 0000000   a   b   c  \r  \n
> > > 0000005
> > > This is with CYGWIN undefined and stty -igncr icrnl
> > > I get the \r no matter what I try for CYGWIN and stty.
> > >
> > > Pierre
> >
> > Pierre,
> >
> > Simple - cat opens files (including stdin) in binary mode, and a Return on
> > the console apparently sends a CRLF.  Try, for example, "cat -s" -- it
> > opens stdin in text mode, and you will not get a CR.  I don't think there
> > currently is an option that controls whether a console Return sends a CR.
> > Intuitively, IMO, it should also be controlled by "binmode".  I'm guessing
> > it's just a matter of copying some code from pipe.cc to fhandler_console.cc
> >       Igor
>
> OK, but don't you expect "od" to also open files in binary mode?

Not sure, have to look at the code.  It's possible "cat" does some weird
fcntl() magic that exposes a bug/feature.

> And what do you make out of this?
> ~: cat /dev/tty | od -c
> abc
> 0000000   a   b   c  \n
> 0000004
>
> Pierre

Ah, but won't this use a different fhandler altogether (fhandler_tty, not
fhandler_console)?  Although I *was* able to reproduce this in an xterm,
which should have used fhandler_tty...  Strange...  Perhaps someone more
knowledgeable in the innards of the tty/console code can chime in and
explain things...
	Igor
-- 
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