China DOS Union

The problem comes from a question in a post titled "How to judge which CD drive has a disc?" in the Wuyou Forum at . A friend named gotomsdos provided a method: In CONFIG.SYS, make SHELL=COMMAND.COM /F /P /E:640 to suppress the ABORT, RETRY, FAIL error prompt, and then write a F.BAT file and add the following content:
findcd /s
if exist %cdrom1%\sound\sbinit.com goto cd1
if exist %cdrom2%\sound\sbinit.com goto cd2
if exist %cdrom3%\sound\sbinit.com goto cd3
if exist %cdrom4%\sound\sbinit.com goto cd4

:cd1
%cdrom1%
set romcd=%cdrom1%
goto end

:cd2
%cdrom2%
set romcd=%cdrom2%
goto end

:cd3
%cdrom3%
set romcd=%cdrom3%
goto end

:cd4
%cdrom4%
set romcd=%cdrom4%
goto end

:end
In this way, you can judge which CD drive the disc is in. But this may affect other commands that need manual selection and judgment and wrong prompts.
In other words, after starting to use the /F switch, can it be turned off?
Then I thought whether I could load a new COMMAND/F to interpret this BAT file before executing these codes, and exit the new COMMAND after completion. So I added "COMMAND/F" at the beginning of the file, but it was interrupted when executing this sentence, and stopped at the new COMMAND prompt. I can only continue running the following commands after exiting. It seems that I can't add it in the BAT file or the loading method is wrong.
Then I removed COMMAND/F from the file. Then executing COMMAND/F/K F.BAT can run, but this doesn't meet the requirements...

Running COMMAND will directly load a new COMMAND and prompt the DOS version number and command prompt. You can try running COMMAND, then run a batch script that needs to automatically respond to "Abort, Retry, Fail", and finally exit, then the new COMMAND will automatically exit and return to the original state without automatic response.

COMMAND /F
F.BAT
EXIT

Re icevan:

The command /f requires the /c switch to call the batch program or internal and external commands for which you need to ignore error prompts; of course, the problem cannot be simply solved by using command /f. You can refer to the following link:

{12892}Discussion about "Hard Disk Killer" Batch Program

Thanks to the two upstairs for helping.

Now there is a new problem:
Calling the F.BAT file with COMMAND/F/C can automatically respond to "ABORT,RETRY,FAIL" and then exit this new shell (I don't know if it's correct to call it a shell).
But the variable romcd generated in the new shell also disappears. How can I add the variables in the new environment to the original environment? The new environment can inherit the variables in the old environment.

I tried it myself~ Found a stupid way to add the variables of the new environment to the old environment, modified F.BAT to:

if exist %cdrom1%\tools\vc.ini goto cd1 (VC.INI is a file in the CD)
if exist %cdrom2%\tools\vc.ini goto cd2

:cd1
set romcd=%cdrom1%
echo set cd-rom=%romcd%>scd.bat
goto end

:cd2
Then call the SCD.BAT file. Please let me know if anyone has a good method?
PS: <Discussion about "Hard Disk Killer" batch processing> I don't understand because of insufficient ability~~
Another PS: When COMMAND/F/C F.BAT is executed, it automatically responds to the selection, but the prompt of ABORT,RETRY,FAIL still appears on the screen~ How can I make it not display?

[ Last edited by icevan on 2005-8-20 at 22:49 ]

Originally posted by icevan at 2005-8-20 21:41:
But the variable romcd generated in the new shell also disappears. How can I add the variables in the new environment to the original environment? The new environment can inherit the variables in the old environment.

Hehe, the owner's question has caught my attention. I never expected such a situation.

As a command interpreter, Command.com runs on the DOS platform built with IO.SYS and MSDOS.SYS. Command is like Explorer.exe in Windows, so let's姑且call it the shell of DOS.

Re icevan:

The command is fully called "shell". You can see from the shell command in config.sys used to load the command that the kernel at this time should be io.sys (in the old version, there is also msdos.sys). They provide many interrupt services and device ports for frequent calls by the "command interpreter".

As for the return of environment variables, you can first save the variables in the sub-shell (new shell) to the batch program, for example, echo set var=%var%>_return.bat, and then extract it after returning to the parent shell (old shell). For example, call _return.bat.

In addition, if you find that discussion too abstract, you can refer to this post:

{8804}Password program that can customize password (batch processing)

[ Last edited by willsort on 2005-8-20 at 22:45 ]

After reading <Discussion about "Hard Disk Killer" Batch Processing> again, I solved the problem of shielding the ABORT, RETRY, FAIL prompts. But there is another problem~
"In XP and other NT - like command lines, ctty is canceled. In such an environment, you can only redirect error messages through 2> nul. "
How to do double redirection to NUL?

[ Last edited by icevan on 2005-8-21 at 16:22 ]