bug#4115: grep and null device

bug#4115: grep and null device

[ts011c8050]

Using emacs 23.1.1 on Windows ( also saw it on emacs 22.x and upgraded )
grep is from cygwin "GNU grep 2.5.3"


Using rgrep always tags on a null device giving lots of output like

grep: NUL: No such file or directory
grep: NUL: No such file or directory
grep: NUL: No such file or directory
grep: NUL: No such file or directory
grep: NUL: No such file or directory

I've tried customising and turning of grep-use-null-device - as from a
quick look at grep.el this is responsible. But no success.

Bug recreated using -no-init-file and -no-site-file



In GNU Emacs 23.1.1 (i386-mingw-nt5.1.2600)
 of 2009-07-30 on SOFT-MJASON
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4)'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENG
  value of $XMODIFIERS: nil
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Custom

Minor modes in effect:
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
M-x r e g <backspace> <backspace> g r e p <return>
<return> * . a s <return> C-a C-k $ F L A S H / <tab>
<return> <backspace> <return> <left> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <right>
<backspace> <backspace> <backspace> <backspace> <backspace>
<backspace> <backspace> <backspace> <backspace> <backspace>
<right> L : <backspace> <backspace> : <return> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<menu-bar> <options> <customize> <customize-group>
g r e p <return> <help-echo> <down-mouse-1> <mouse-1>
<wheel-down> <double-wheel-down> <triple-wheel-down>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <down-mouse-1> <help-echo> <mouse-movement>
<drag-mouse-1> <help-echo> <down-mouse-1> <help-echo>
<down-mouse-1> <help-echo> <help-echo> <down-mouse-1>
<mouse-1> M-x r g r e p <return> <return> <return>
<return> <help-echo> <down-mouse-1> <mouse-1> <wheel-down>
<double-wheel-down> M-x r g r e p <return> <return>
<return> <return> <help-echo> <down-mouse-1> <mouse-1>
M-x r e p o r t - e m <tab> <return>

Recent messages:
Creating group...
Creating group members... 91%
Creating group magic...
Creating group state...
Creating group... done
Creating customization items ...done
Resetting customization items...done
Creating customization setup...done
To install your edits, invoke [State] and choose the Set operation
Grep finished (matches found) [2 times]

bug#4115: grep and null device

[Eli Zaretskii]

> Date: Tue, 11 Aug 2009 09:41:50 +0100 (BST)
> From: ts011c8050@blueyonder.co.uk
> Cc: 
> 
> Using emacs 23.1.1 on Windows ( also saw it on emacs 22.x and upgraded )
> grep is from cygwin "GNU grep 2.5.3"
> 
> 
> Using rgrep always tags on a null device giving lots of output like
> 
> grep: NUL: No such file or directory

Does Cygwin support NUL as the Windows null device?  If not, that's
your problem.

Doesn't `rgrep' also invoke `find'?  (It should show the full command
it is running in the "*grep*" buffer.)  If so, what port of `find' are
you using?

bug#4115: grep and null device

[Eli Zaretskii]

> From: "shippeys" <theshippeys@blueyonder.co.uk>
> Date: Tue, 11 Aug 2009 19:53:05 +0100

Please use Reply-All, to let the bug-tracker archive all the
discussion.

> > > grep: NUL: No such file or directory
> > 
> > Does Cygwin support NUL as the Windows null device?  If not, that's
> > your problem.
> > 
> 
> Yes - Would it be the grep.el code that gets confused and picks NUL?

You are using a native Windows port of Emacs.  NUL is the standard
name of the null device on that system.  Why do you think it gets
confused?

> AIUI the null device is only there to make sure the grep call doesn't hang
> if you forget to pass it files to search. It seems a lot of pain for a
> marginal benefit!

I don't know yet why null device is there.  Seeing the command line
would help.

bug#4115: grep and null device

[Jason Rumney]

Eli Zaretskii wrote:

>> AIUI the null device is only there to make sure the grep call doesn't hang
>> if you forget to pass it files to search. It seems a lot of pain for a
>> marginal benefit!
>>     
>
> I don't know yet why null device is there.  Seeing the command line
> would help.
>   

It is there to force grep to print filenames in its output, even if only 
a single filename is given on the command line.

bug#4115: grep and null device

[Eli Zaretskii]

> From: "Tom Shippey" <tomshippey@blueyonder.co.uk>
> Date: Tue, 11 Aug 2009 23:00:38 +0100
> 
> find . \( -path \*/SCCS -o -path \*/RCS -o -path \*/CVS -o -path \*/MCVS -o
> -path \*/.svn -o -path \*/.git -o -path \*/.hg -o -path \*/.bzr -o -path
> \*/_MTN -o -path \*/_darcs -o -path \*/\{arch\} \) -prune -o  -type f \(
> -iname \*.c \) -exec grep -i -n junk {} NUL \;
> ./x.c:1:junk
> ./x.c:3:junk
> grep: NUL: No such file or directory
> grep: NUL: No such file or directory

Does it help to set null-device to "/dev/null"?

bug#4115: marked as done (grep and null device)

[Emacs bug Tracking System]

[-- Attachment #1: Type: text/plain, Size: 832 bytes --]


Your message dated Wed, 12 Aug 2009 20:32:38 +0300
with message-id <83my65j5u1.fsf@gnu.org>
and subject line Re: bug#4115: grep and null device
has caused the Emacs bug report #4115,
regarding grep and null device
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
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-- 
4115: http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=4115
Emacs Bug Tracking System
Contact owner@emacsbugs.donarmstrong.com with problems

[-- Attachment #2: Type: message/rfc822, Size: 5507 bytes --]

From: ts011c8050@blueyonder.co.uk
To: bug-gnu-emacs@gnu.org
Subject: grep and null device
Date: Tue, 11 Aug 2009 09:41:50 +0100 (BST)
Message-ID: <3988.84.19.238.174.1249980110.UEIUQ2lbQEh6Qw==.squirrel@84.19.238.174>

Using emacs 23.1.1 on Windows ( also saw it on emacs 22.x and upgraded )
grep is from cygwin "GNU grep 2.5.3"


Using rgrep always tags on a null device giving lots of output like

grep: NUL: No such file or directory
grep: NUL: No such file or directory
grep: NUL: No such file or directory
grep: NUL: No such file or directory
grep: NUL: No such file or directory

I've tried customising and turning of grep-use-null-device - as from a
quick look at grep.el this is responsible. But no success.

Bug recreated using -no-init-file and -no-site-file



In GNU Emacs 23.1.1 (i386-mingw-nt5.1.2600)
 of 2009-07-30 on SOFT-MJASON
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4)'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENG
  value of $XMODIFIERS: nil
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Custom

Minor modes in effect:
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
M-x r e g <backspace> <backspace> g r e p <return>
<return> * . a s <return> C-a C-k $ F L A S H / <tab>
<return> <backspace> <return> <left> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <right>
<backspace> <backspace> <backspace> <backspace> <backspace>
<backspace> <backspace> <backspace> <backspace> <backspace>
<right> L : <backspace> <backspace> : <return> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<menu-bar> <options> <customize> <customize-group>
g r e p <return> <help-echo> <down-mouse-1> <mouse-1>
<wheel-down> <double-wheel-down> <triple-wheel-down>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <down-mouse-1> <help-echo> <mouse-movement>
<drag-mouse-1> <help-echo> <down-mouse-1> <help-echo>
<down-mouse-1> <help-echo> <help-echo> <down-mouse-1>
<mouse-1> M-x r g r e p <return> <return> <return>
<return> <help-echo> <down-mouse-1> <mouse-1> <wheel-down>
<double-wheel-down> M-x r g r e p <return> <return>
<return> <return> <help-echo> <down-mouse-1> <mouse-1>
M-x r e p o r t - e m <tab> <return>

Recent messages:
Creating group...
Creating group members... 91%
Creating group magic...
Creating group state...
Creating group... done
Creating customization items ...done
Resetting customization items...done
Creating customization setup...done
To install your edits, invoke [State] and choose the Set operation
Grep finished (matches found) [2 times]






[-- Attachment #3: Type: message/rfc822, Size: 2510 bytes --]

From: Eli Zaretskii <eliz@gnu.org>
To: Tom Shippey <tomshippey@blueyonder.co.uk>
Cc: 4115-done@emacsbugs.donarmstrong.com
Subject: Re: bug#4115: grep and null device
Date: Wed, 12 Aug 2009 20:32:38 +0300
Message-ID: <83my65j5u1.fsf@gnu.org>

> From: "Tom Shippey" <tomshippey@blueyonder.co.uk>
> Date: Wed, 12 Aug 2009 08:50:57 +0100
> 
> > > find . \( -path \*/SCCS -o -path \*/RCS -o -path \*/CVS -o -path
> > \*/MCVS -o
> > > -path \*/.svn -o -path \*/.git -o -path \*/.hg -o -path \*/.bzr -o -
> > path
> > > \*/_MTN -o -path \*/_darcs -o -path \*/\{arch\} \) -prune -o  -type f
> > \(
> > > -iname \*.c \) -exec grep -i -n junk {} NUL \;
> > > ./x.c:1:junk
> > > ./x.c:3:junk
> > > grep: NUL: No such file or directory
> > > grep: NUL: No such file or directory
> > 
> > Does it help to set null-device to "/dev/null"?
> 
> Yep - that works fine. Many thanks.

Thanks.  I'm closing the bug, because its reason is mixing a native
Windows build of Emacs with Cygwin shell that apparently does not
support NUL as the null device.