Diff on Emacs

Diff on Emacs

[Jasen]

Hi,

How do I enable diff on Emacs?  Doesn't diff a standard built-in 
function in Emacs?  Wheh I try to diff two buffers, i got "no such file 
or directory" error that doesn't sound right, what did I miss here?

Thanks,
Jasen

Re: Diff on Emacs

[Jasen]

Jasen wrote:
> Hi,
> 
> How do I enable diff on Emacs?  Doesn't diff a standard built-in 
> function in Emacs?  Wheh I try to diff two buffers, i got "no such file 
> or directory" error that doesn't sound right, what did I miss here?
> 
> Thanks,
> Jasen
> 

Sorry, forgot to tell you that I'm using Emacs 21.2.1 on Windows XP.

Thanks,
Jasen

Re: Diff on Emacs

[Jesper Harder]

Jasen <xx@yy.zz> writes:

>> How do I enable diff on Emacs?  Doesn't diff a standard built-in
>> function in Emacs?  Wheh I try to diff two buffers, i got "no such
>> file or directory" error that doesn't sound right, what did I miss
>> here?
>
> Sorry, forgot to tell you that I'm using Emacs 21.2.1 on Windows XP.

Ah, then you need to install the 'diff' program from somewhere.  One
possibility is to get it from the Cygwin tools.

Re: Diff on Emacs

[Jasen]

There are many diff*.el and ediff*.el files in ../lisp/ directory so 
isn't diff a standard built-in function for emacs?

Jasen

Jesper Harder wrote:

> Jasen <xx@yy.zz> writes:
> 
> 
>>>How do I enable diff on Emacs?  Doesn't diff a standard built-in
>>>function in Emacs?  Wheh I try to diff two buffers, i got "no such
>>>file or directory" error that doesn't sound right, what did I miss
>>>here?
>>
>>Sorry, forgot to tell you that I'm using Emacs 21.2.1 on Windows XP.
> 
> 
> Ah, then you need to install the 'diff' program from somewhere.  One
> possibility is to get it from the Cygwin tools.

Re: Diff on Emacs

[Joakim Hove]

Jasen <xx@yy.zz> writes:

> There are many diff*.el and ediff*.el files in ../lisp/ directory so
> isn't diff a standard built-in function for emacs?

Snipped from diff.el:

  ;; This package helps you explore differences between files, using the
  ;; UNIX command diff(1).  The commands are `diff' and `diff-backup'.
  ;; You can specify options with `diff-switches'.

So, altough diff.el is standard emacs, it is based on the external
program diff, which is standard on Unix varieties, but obviously not
on Win XP. 


HTH - Joakim


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Re: Diff on Emacs

[Barman Brakjoller]

>   ;; This package helps you explore differences between files, using the
>   ;; UNIX command diff(1).  The commands are `diff' and `diff-backup'.
>   ;; You can specify options with `diff-switches'.
> 
> So, altough diff.el is standard emacs, it is based on the external
> program diff, which is standard on Unix varieties, but obviously not
> on Win XP. 

A lot of unix tools has been natively ported to Windows:

http://unxutils.sourceforge.net/

Works extremely well and no need for cygwin-dlls and stuff.

Re: Diff on Emacs

[Alan Mackenzie]

Jasen <xx@yy.zz> wrote on Mon, 10 Nov 2003 21:30:59 -0800:

> Jesper Harder wrote:

>> Jasen <xx@yy.zz> writes:

>>>>How do I enable diff on Emacs?  Doesn't diff a standard built-in
>>>>function in Emacs?  Wheh I try to diff two buffers, i got "no such
>>>>file or directory" error that doesn't sound right, what did I miss
>>>>here?

>>>Sorry, forgot to tell you that I'm using Emacs 21.2.1 on Windows XP.

>> Ah, then you need to install the 'diff' program from somewhere.  One
>> possibility is to get it from the Cygwin tools.

> There are many diff*.el and ediff*.el files in ../lisp/ directory so 
> isn't diff a standard built-in function for emacs?

Let me clarify Jesper's post:

All these elisp files eventually call a separate executable program
"diff.exe".  There is no such program included in Microsoft operating
systems (guess why we all prefer GNU/linux?  :-), and that is what your
error message ("no such file...") is about.

So you're going to have to install diff.exe yourself.  A good place to
download it from would be <http://www.cygwin.org/>  (If I remember the
URL correctly - if not, do a Web search for "cygwin").

> Jasen

-- 
Alan Mackenzie (Munich, Germany)
Email: aacm@muuc.dee; to decode, wherever there is a repeated letter
(like "aa"), remove half of them (leaving, say, "a").

Re: Diff on Emacs

[LEE Sau Dan]

>>>>> "Jasen" == Jasen  <xx@yy.zz> writes:

    Jasen> There are many diff*.el and ediff*.el files in ../lisp/
    Jasen> directory so isn't diff a standard built-in function for
    Jasen> emacs?

No.  The  'diff' utility  works so  well and is  so verstaile  that it
doesn't  make  sense  to  reinvent  the  wheel  and  incorporate  this
reinvented wheel into Emacs.



-- 
Lee Sau Dan                     李守敦(Big5)                    ~{@nJX6X~}(HZ) 

E-mail: danlee@informatik.uni-freiburg.de
Home page: http://www.informatik.uni-freiburg.de/~danlee

Re: Diff on Emacs

[Juri Linkov]

Jasen <xx@yy.zz> writes:
> There are many diff*.el and ediff*.el files in ../lisp/ directory so
> isn't diff a standard built-in function for emacs?

To compare two buffers you can use Emacs function `compare-windows'
from compare-w.el which now implements a simple diff algorithm.
Instead of line by line output of the 'diff' program, `compare-windows'
provides differences character by character which produces more
fine-grained results than the 'diff' program.

-- 
http://www.jurta.org/emacs/

Re: Diff on Emacs

[LEE Sau Dan]

>>>>> "Juri" == Juri Linkov <juri@jurta.org> writes:

    Juri> Jasen <xx@yy.zz> writes:
    >> There are many diff*.el and ediff*.el files in ../lisp/
    >> directory so isn't diff a standard built-in function for emacs?

    Juri> To compare two buffers you can use Emacs function
    Juri> `compare-windows' from compare-w.el which now implements a
    Juri> simple diff algorithm.  Instead of line by line output of
    Juri> the 'diff' program, `compare-windows' provides differences
    Juri> character by character which produces more fine-grained
    Juri> results than the 'diff' program.

M-x  ediff-buffers gives  you a  diff output  that can  be  refined to
character-based diff.



-- 
Lee Sau Dan                     李守敦(Big5)                    ~{@nJX6X~}(HZ) 

E-mail: danlee@informatik.uni-freiburg.de
Home page: http://www.informatik.uni-freiburg.de/~danlee

Re: Diff on Emacs

[Juri Linkov]

LEE Sau Dan <danlee@informatik.uni-freiburg.de> writes:
>>>>>> "Juri" == Juri Linkov <juri@jurta.org> writes:
>     Juri> Jasen <xx@yy.zz> writes:
>     >> There are many diff*.el and ediff*.el files in ../lisp/
>     >> directory so isn't diff a standard built-in function for emacs?
>     Juri> To compare two buffers you can use Emacs function
>     Juri> `compare-windows' from compare-w.el which now implements a
>     Juri> simple diff algorithm.  Instead of line by line output of
>     Juri> the 'diff' program, `compare-windows' provides differences
>     Juri> character by character which produces more fine-grained
>     Juri> results than the 'diff' program.
>
> M-x  ediff-buffers gives  you a  diff output  that can  be  refined to
> character-based diff.

This is not completely true.  Ediff refinements are word-based.
Although this is a big improvement over line-based diff output,
this is not the same thing as character-based `compare-windows'.

-- 
http://www.jurta.org/emacs/

Re: Diff on Emacs

[Kevin Rodgers]

Juri Linkov wrote:

> LEE Sau Dan <danlee@informatik.uni-freiburg.de> writes:
>>M-x  ediff-buffers gives  you a  diff output  that can  be  refined to
>>character-based diff.
> 
> This is not completely true.  Ediff refinements are word-based.
> Although this is a big improvement over line-based diff output,
> this is not the same thing as character-based `compare-windows'.

But you can (setq ediff-forward-word-function 'forward-char).

-- 
Kevin Rodgers

Re: Diff on Emacs

[kgold]

Jesper Harder <harder@myrealbox.com> writes:
> Jasen <xx@yy.zz> writes:
> 
> >> How do I enable diff on Emacs?  Doesn't diff a standard built-in
> >> function in Emacs?  Wheh I try to diff two buffers, i got "no such
> >> file or directory" error that doesn't sound right, what did I miss
> >> here?
> >
> > Sorry, forgot to tell you that I'm using Emacs 21.2.1 on Windows XP.
> 
> Ah, then you need to install the 'diff' program from somewhere.  One
> possibility is to get it from the Cygwin tools.

If you don't want the entire Cygwin environment, you can get individual
Unix utilities.  For example:

	http://unxutils.sourceforge.net/

Re: Diff on Emacs

[Jasen]

Thank you very much for everyone's help.  Now the problem resolved.

Jasen



kgold wrote:
> Jesper Harder <harder@myrealbox.com> writes:
> 
>>Jasen <xx@yy.zz> writes:
>>
>>
>>>>How do I enable diff on Emacs?  Doesn't diff a standard built-in
>>>>function in Emacs?  Wheh I try to diff two buffers, i got "no such
>>>>file or directory" error that doesn't sound right, what did I miss
>>>>here?
>>>
>>>Sorry, forgot to tell you that I'm using Emacs 21.2.1 on Windows XP.
>>
>>Ah, then you need to install the 'diff' program from somewhere.  One
>>possibility is to get it from the Cygwin tools.
> 
> 
> If you don't want the entire Cygwin environment, you can get individual
> Unix utilities.  For example:
> 
> 	http://unxutils.sourceforge.net/
> 

RE: Diff on Emacs

[Victor Kirk]

Alan Mackenzie said:
> So you're going to have to install diff.exe yourself.  A good place to
> download it from would be <http://www.cygwin.org/>  (If I remember the
> URL correctly - if not, do a Web search for "cygwin").

Or better still (depending on your view of cygwin), either of

http://unxutils.sourceforge.net/
http://gnuwin32.sourceforge.net/


Regards,

Vic
--
Victor Kirk
Analyst
Serco Integrated Transport
Tel: +44 (0)1287 611225
Fax: +44 (0)1287 610360
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