How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

Post by George Schi » Sun, 27 Aug 1995 04:00:00



All MS-DOS versions prior to 5.0 allowed simple editing of the AUTOEXEC.BAT
string in COMMAND.COM to startup a different batch file. This doesn't work with
subsequent versions. Billy must have hidden an encrypted startup string
elsewhere.

Has anyone been able to locate it or am I just rompin' down the wrong road?

 
 
 

How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

Post by Gerry Kro » Mon, 28 Aug 1995 04:00:00



Quote:>All MS-DOS versions prior to 5.0 allowed simple editing of the

 AUTOEXEC.BAT

Quote:>string in COMMAND.COM to startup a different batch file. This doesn't work
>with
>subsequent versions. Billy must have hidden an encrypted startup string
>elsewhere.
>Has anyone been able to locate it or am I just rompin' down the wrong  

 road?

You need to change the SHELL command in CONFIG.SYS to specify a different
command file when COMMAND.COM starts.  Check the on-line help for the
proper option.  I think it's /K, but I'm not sure, since I don't have ready
access to one of the systems I set this up on.

Good luck.  Gerry Kroll, PWGSC, Government of Canada

 
 
 

How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

Post by George Schi » Mon, 28 Aug 1995 04:00:00




>>All MS-DOS versions prior to 5.0 allowed simple editing of the AUTOEXEC.BAT
>>string in COMMAND.COM to startup a different batch file. This doesn't work
>>with subsequent versions. Billy must have hidden an encrypted startup string
>>elsewhere.

>>Has anyone been able to locate it or am I just rompin' down the wrong  road?

>You need to change the SHELL command in CONFIG.SYS to specify a different
>command file when COMMAND.COM starts.  Check the on-line help for the
>proper option.  I think it's /K, but I'm not sure, since I don't have ready
>access to one of the systems I set this up on.

>Good luck.  Gerry Kroll, PWGSC, Government of Canada

Gerry,

I should have been more clear.

CONFIG.SYS and AUTOEXEC.BAT must NOT be touched. Only a change to
COMMAND.COM is an option.

Thanks anyway,
Geo

P.S. Any more takers?

 
 
 

How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

Post by s.. » Wed, 30 Aug 1995 04:00:00



|> All MS-DOS versions prior to 5.0 allowed simple editing of the AUTOEXEC.BAT
|> string in COMMAND.COM to startup a different batch file. This doesn't work with
|> subsequent versions. Billy must have hidden an encrypted startup string
|> elsewhere.

|> Has anyone been able to locate it or am I just rompin' down the wrong road?

        4DOS allows you to call your startup batch file anything you want.
        In my case I call it startup.btm.
        As for MS DOS, well who knows!
_________________________________________________________________
 The only certainty about British weather is that it's uncertain
_________________________________________________________________
<beija-flor>, London, England, European Union

 
 
 

How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

Post by Jerry Cowa » Wed, 30 Aug 1995 04:00:00


GS>>Subject: How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

GS>>All MS-DOS versions prior to 5.0 allowed simple editing of the AUTOEXEC.BAT
GS>>string in COMMAND.COM to startup a different batch file. This doesn't work

GS>>subsequent versions. Billy must have hidden an encrypted startup string
GS>>elsewhere.

Try doing a hex search for 2E4558452E424154 with some sort of hex
editor. Here is the breakdown: in hex     2E 45 58 45 2E 42 41 54
                               in ASCII    .  E  X  E  .  B  A  T

Using Norton's Diskedit, the BAT extension started at offset 49,808,
hex C290.

Changing the last 3 values should allow you to change the extension of
your batch files. However, I believe that this will affect ALL batch
files, not just the autoexec.bat file.

Don't forget to make a backup of the command.com before you edit it...
...just in case :)

Hope this helps, Jerry
---
 t OLX 2.1    t Oh sure!  But what's the speed of dark?

 
 
 

How to Patch COMMAND.COM to not use AUTOEXEC.BAT?

Post by nata.. » Thu, 31 Aug 1995 04:00:00



> All MS-DOS versions prior to 5.0 allowed simple editing of the AUTOEXEC.BAT
> string in COMMAND.COM to startup a different batch file. This doesn't work with
> subsequent versions. Billy must have hidden an encrypted startup string
> elsewhere.

> Has anyone been able to locate it or am I just rompin' down the wrong road?

I just tried it on COMMAND.COM from MS-DOS 6.2. It worked fine after some
tweaking. I won't go into the changes I made that did NOT work--only the
ones that did.

The AUTOEXEC.BAT string occurs twice in COMMAND.COM. I edited both (using
Norton's disk editor) so that they were changed to the same string that was
of *EQUAL LENGTH* to "AUTOEXEC.BAT" (8+3 filename). These changes were
made to COMMAND.COM itself. I backed up my original with a different name
first, of course! :)

A few interesting observations without explanation (I didn't do much
experimentation):

        1) I could not use a patched COMMAND.COM that had a different
name, even if I set the new name in CONFIG.SYS with the shell command.

        2) When my original tests did not work, I found that I did not
need to use a boot disk. I simply re-booted and pressed <F5> to bypass
the startup files. To my surprise, I was prompted for the proper name
of the COMMAND.COM file. When I entered it (in this case COMMAND.BAK),
I was able to use the system to make the necessary restoration.

--
Darren Natale

Function DISCLAIMER:string[80];
  begin
    case ABOVE of
      'OPINION' : DISCLAIMER:=' is my own, but should be yours too.';
      'FACT'    : DISCLAIMER:=' was made up by me, so you can believe it.';
      'BATCH'   : DISCLAIMER:=' probably contains at least one error.';
      'FLAME'   : DISCLAIMER:=' was written by someone else using my account.';
    end;
    DISCLAIMER:='The above '+ABOVE+DISCLAIMER;
  end;

 
 
 

1. How to patch COMMAND.COM to not use AUTOEXEC.BAT?

I have a situation that requires starting a machine with a file other than
AUTOEXEC.BAT. This must be accomplished without changing CONFIG.SYS or
AUTOEXEC.BAT in any way.

All MS-DOS versions prior to 5.0 allowed simply editing the AUTOEXEC.BAT
string in COMMAND.COM to startup a different batch file. This doesn't work with
subsequent versions. Billy must have hidden an encrypted startup string
elsewhere.

Has anyone been able to locate it or am I just rompin' down the wrong road?

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