GNU bug report logs - #33774
glitch in cat

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 33774 in the body.
You can then email your comments to 33774 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Valentin Schild <valentinschild <at> gmail.com>
To: bug-coreutils <at> gnu.org
Subject: glitch in cat
Date: Sun, 16 Dec 2018 20:58:39 +0100

[Message part 1 (text/plain, inline)]

Hi,

somehow, when using cat to display a file's content, I get output to
the command line
The file to output contains
^[Z
like attached file "catbug".

In terminal I type
cat catbug

[catbug (application/octet-stream, attachment)]

Message #8 received at 33774 <at> debbugs.gnu.org (full text, mbox):

From: Bernhard Voelker <mail <at> bernhard-voelker.de>
To: Valentin Schild <valentinschild <at> gmail.com>, 33774 <at> debbugs.gnu.org
Subject: Re: bug#33774: glitch in cat
Date: Wed, 19 Dec 2018 14:01:38 +0100

tags 33774 notabug
close 33774
stop

On 12/16/18 8:58 PM, Valentin Schild wrote:
> somehow, when using cat to display a file's content, I get output to
> the command line
> The file to output contains
> ^[Z
> like attached file "catbug".
> 
> In terminal I type
> cat catbug

That's the point: the terminal treats some control characters specially,
and therefore does not display them.

Your file contains 3 bytes:
- octal 33,
- a 'Z', and
- octal 12 (=newline):

  od -to1z catbug
  0000000 033 132 012                                                      >.Z.<
  0000003

And cat(1) is exactly writing that to the terminal:

  $ strace -ve write cat catbug
  write(1, "\33Z\n", 3)                   = 3
  +++ exited with 0 +++

As there seems nothing to be wrong in 'cat', I'm marking this as not a bug
in our bug tracker.  Of course, discussion on this may continue, and we may
even re-open this issue if needed.

Have a nice day,
Berny

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.