command.com versus cmd.exe

command.com versus cmd.exe

[Kai Großjohann]

I don't use Windows myself, but I think that some versions of Windows
use command.com as interpreter for commands and others use cmd.exe.
Is this true?

If it is true, how would a Lisp package know which one to use?
shell-file-name?  system-type?

kai
-- 
~/.signature is: umop 3p!sdn    (Frank Nobis)

Re: command.com versus cmd.exe

[Klaus Berndl]

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On Thu, 12 Sep 2002, Kai Großjohann wrote:

>  I don't use Windows myself, but I think that some versions of Windows
>  use command.com as interpreter for commands and others use cmd.exe.
>  Is this true?
>  
>  If it is true, how would a Lisp package know which one to use?
>  shell-file-name?  system-type?

Do not know exactly but IMHO all modern Windows system use cmd.exe and only
old completely  DOS-based 16 bit windows systems like Windows 3.11 use
command.com...but i'm not sure....

Please correct me!

But it should not matter because i would recommend to check the
environment-variable COMSPEC (which is set always be every windows system!),
maybe like follows:

If you need the command interpreter of windows with full path do:

,----
| (expand-file-name (getenv "COMSPEC"))
`----

If you only want the name of the interpreter do:

,----
| (file-name-nondirectory (expand-file-name (getenv "COMSPEC")))
`----

Ciao,
Klaus

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-- 
Klaus Berndl			mailto: klaus.berndl@sdm.de
sd&m AG				http://www.sdm.de
software design & management
Thomas-Dehler-Str. 27, 81737 München, Germany
Tel +49 89 63812-392, Fax -220

Re: command.com versus cmd.exe

[Kai Großjohann]

Klaus Berndl <Klaus.Berndl@raibau.raiffeisen.at> writes:

> But it should not matter because i would recommend to check the
> environment-variable COMSPEC (which is set always be every windows system!),
> maybe like follows:

Ah, I didn't know about COMSPEC.  I now use the following code to
initialize the variable:

  (if (memq system-type '(windows-nt))
      (getenv "COMSPEC")
    "/bin/sh")

Are there other values of system-type that I should check for?

kai
-- 
~/.signature is: umop 3p!sdn    (Frank Nobis)

Re: command.com versus cmd.exe

[Klaus Berndl]

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On Thu, 12 Sep 2002, Kai Großjohann wrote:

>  Klaus Berndl <Klaus.Berndl@raibau.raiffeisen.at> writes:
>  
> > But it should not matter because i would recommend to check the
> > environment-variable COMSPEC (which is set always be every windows
> > system!), maybe like follows:
>  
>  Ah, I didn't know about COMSPEC.  I now use the following code to
>  initialize the variable:
>  
>    (if (memq system-type '(windows-nt))
>        (getenv "COMSPEC")
>      "/bin/sh")
>  Are there other values of system-type that I should check for?

The info manual says for *system-type*:

,----
| ...
|     `ms-dos'
|           Microsoft MS-DOS "operating system."  Emacs compiled with
|           DJGPP for MS-DOS binds `system-type' to `ms-dos' even when
|           you run it on MS-Windows.
| ...
`----

but i think today MS-DOS is not relevant anymore.

But i'm not sure about *cygwin32* as system-type. For the cygwin port of
recent XEmacs system-type is set to this value, don't know what value is set
for the cygwin port of GNU Emacs 21.2 (which seems to available now).

COMSPEC is also set for the cygwin-suite (because it "ingerits" the env-vars
of Windows) and it has normally the value "cmd.exe".

Because i do not know for which purpose you need the command-interpreter of
windows i can not say what is better for cygwin-ports of (X)Emacs: the value
of COMSPEC or "/bin/sh" (which is of course available on cygwin-systems)?!

Summary: Dependent of the usage you maybe want to check also for *cygwin32*!

Ciao,
Klaus

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-- 
Klaus Berndl			mailto: klaus.berndl@sdm.de
sd&m AG				http://www.sdm.de
software design & management
Thomas-Dehler-Str. 27, 81737 München, Germany
Tel +49 89 63812-392, Fax -220

Re: command.com versus cmd.exe

[Jochen Küpper]

On 12 Sep 2002 14:45:55 +0200 Klaus Berndl wrote:

Klaus> But i'm not sure about *cygwin32* as system-type. For the
Klaus> cygwin port of recent XEmacs system-type is set to this value,
Klaus> don't know what value is set for the cygwin port of GNU Emacs
Klaus> 21.2 (which seems to available now).

emacs-21.2 on cygwin has
,----
| system-type's value is cygwin
| 
| Documentation:
| Value is symbol indicating type of operating system you are using.
`----

Greetings,
Jochen
-- 
Einigkeit und Recht und Freiheit                http://www.Jochen-Kuepper.de
    Liberté, Égalité, Fraternité                GnuPG key: 44BCCD8E
        Sex, drugs and rock-n-roll

Re: command.com versus cmd.exe

[lawrence mitchell]

Kai Grossjohann wrote:

[...]

> Ah, I didn't know about COMSPEC.  I now use the following code to
> initialize the variable:

>   (if (memq system-type '(windows-nt))
>       (getenv "COMSPEC")
>     "/bin/sh")

How about (or (getenv "COMSPEC") "/bin/sh") ?  Though I suppose
somebody might have defined an environment variable named COMSPEC
themselves.

> Are there other values of system-type that I should check for?

DOS and maybe (probably?) Cygwin I'd guess.  What about OS/2?[1]

[1] Someone help me!
-- 
lawrence mitchell <wence@gmx.li>

Re: command.com versus cmd.exe

[Kai Großjohann]

lawrence mitchell <wence@gmx.li> writes:

> Kai Grossjohann wrote:
>
> [...]
>
>> Ah, I didn't know about COMSPEC.  I now use the following code to
>> initialize the variable:
>
>>   (if (memq system-type '(windows-nt))
>>       (getenv "COMSPEC")
>>     "/bin/sh")
>
> How about (or (getenv "COMSPEC") "/bin/sh") ?  Though I suppose
> somebody might have defined an environment variable named COMSPEC
> themselves.

That looks like a good idea.

kai
-- 
~/.signature is: umop 3p!sdn    (Frank Nobis)

Re: command.com versus cmd.exe

[FRC]

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My advice would be not to use (crappy) MS stuff whenever possible and stick
to the cygwin shells.

"lawrence mitchell" <wence@gmx.li> a écrit dans le message de news:
wkwuprxt1e.fsf@ID-97657.usr.dfncis.de...
> Kai Grossjohann wrote:
>
> [...]
>
> > Ah, I didn't know about COMSPEC.  I now use the following code to
> > initialize the variable:
>
> >   (if (memq system-type '(windows-nt))
> >       (getenv "COMSPEC")
> >     "/bin/sh")
>
> How about (or (getenv "COMSPEC") "/bin/sh") ?  Though I suppose
> somebody might have defined an environment variable named COMSPEC
> themselves.
>
> > Are there other values of system-type that I should check for?
>
> DOS and maybe (probably?) Cygwin I'd guess.  What about OS/2?[1]
>
> [1] Someone help me!
> --
> lawrence mitchell <wence@gmx.li>

Re: command.com versus cmd.exe

[Zhongtao Zhu]

Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai Großjohann) writes:

> I don't use Windows myself, but I think that some versions of Windows
> use command.com as interpreter for commands and others use cmd.exe.
> Is this true?
> 
> If it is true, how would a Lisp package know which one to use?
> shell-file-name?  system-type?

In Emacs source tree there is a nt/ directory containing support for
compiling and running GNU Emacs on MS Windows 95/98/nt/xp. I'd like to
cite two paragraphs from cmdproxy.c as follows:

   Accepts subset of Unix sh(1) command-line options, for
   compatability with elisp code written for Unix.  When possible,
   executes external programs directly (a common use of /bin/sh by
   Emacs), otherwise invokes the user-specified command processor to
   handle built-in shell commands, batch files and interactive mode.

   The main function is simply to process the "-c string" option in
   the way /bin/sh does, since the standard Windows command shells use
   the convention that everything after "/c" (the Windows equivalent
   of "-c") is the input string.

I think this would be a hint to Kai's question. 

By building Emacs from the nt/ directory in MS Windows, every thing
works successfully well. I now check the variable `shell-file-name' in
my machine it is set with "D:/emacs/bin/cmdproxy.exe".

In other experiment I've performed by net-install the pre-compiled
binaries without X11 in MS Windows, the installed Emacs when running
in cmd.exe seems insane since it cannot even be terminated by C-x
C-c. I wonder if this is exactly related to Kai's hesitation.
-- 
Zhongtao Zhu                          Tel: +86 10 6278 2266
Department of Computer, Tsinghua University, Beijing, China

Re: command.com versus cmd.exe

[Kai Großjohann]

Zhongtao Zhu <zhongtao@tsinghua.edu.cn> writes:

> By building Emacs from the nt/ directory in MS Windows, every thing
> works successfully well. I now check the variable `shell-file-name' in
> my machine it is set with "D:/emacs/bin/cmdproxy.exe".

Cool, then I can just use that!  Hm.

kai
-- 
~/.signature is: umop 3p!sdn    (Frank Nobis)

Re: command.com versus cmd.exe

[Klaus Berndl]

On Thu, 12 Sep 2002, Kai Großjohann wrote:



>  Zhongtao Zhu <zhongtao@tsinghua.edu.cn> writes:
>  
> > By building Emacs from the nt/ directory in MS Windows, every thing
> > works successfully well. I now check the variable `shell-file-name' in
> > my machine it is set with "D:/emacs/bin/cmdproxy.exe".
>  
>  Cool, then I can just use that!  Hm.

If you do not need the distinction between cmd.exe and command.com for special
purposes (do not know) nut only a mechanism to execute stuff with the
windows-system then you should definitely use cmdproxy.exe.  I agree
completely with Zhongtao!

Klaus

-- 
Klaus Berndl			mailto: klaus.berndl@sdm.de
sd&m AG				http://www.sdm.de
software design & management
Thomas-Dehler-Str. 27, 81737 München, Germany
Tel +49 89 63812-392, Fax -220