China DOS Union

How to get the value returned after a command is executed?
For example, there is a file named a.txt with content:
1
Using the type command:
C:\>TYPE A.TXT
C:\>1
How to get the 1 displayed after the type command is executed in a batch script and add 1 to it, then save it into a.txt, that is, the content of a.txt becomes 2.
C:\>TYPE A.TXT
C:\>2

Environment requirements: DOS6.22 or DOS7.1

Thank you!

for /f %%a in (a.txt) do set /a pp=%%a+1
echo %pp% > a.txt

The person upstairs, can it be used under DOS? Hehe.

test1.bat
call test2.bat 1 2 3 4 5 6 7 8 9

test2.bat
:start1 if "%1"=="" goto end find "%1" A.TXT if errorlevel 0 goto xxx shift goto start1 :xxx shift echo %1>A.TXT :end

Give an idea, the code is not tested

The test code is okay. It's just that the execution result echo %1>A.TXT is actually echo 2>A.TXT, so we need to add the escape definition symbol echo ^%1>A.TXT

Strengthen judgment of errorlevel return value

test1.bat
@echo off call test2.bat 1 2 3 4 5 6 7 8 9

test2.bat
:start1 if "%1"=="" goto end find "%1" A.TXT>nul if not errorlevel 1 if errorlevel 0 goto xxx shift goto start1 goto end :xxx shift echo ^%1>A.TXT :end

What went wrong during the test? There are two issues:
(1) A prompt "General error reading drive F" appears.
(2) After running test1.bat for the second time, the result is still 2 instead of becoming 3.
Please give guidance.

Here are the running results

E:\>TYPE A.TXT
1

E:\>TEST1

General error reading drive F
A: Abort, R: Retry, F: Fail? a
E:\>type a.txt
2

e:\>test1

General error reading drive F
A: Abort, R: Retry, F: Fail? a
E:\>type a.txt
2

I don't know how to attach pictures, so I have to type them out

General errors occur when reading drive F, which has nothing to do with the code. The code part did not attempt to access drive F.

The pure DOS code is unstable and easily causes errors like "general error reading drive F". Please check if your batch code has parts that access drive F, or do not load the CD-ROM driver.

In addition, you can test the code on floor 6 under XP. The code is universal for pure DOS and XP. Just change echo ^%1>A.TXT to echo %1>A.TXT in pure DOS.

[ Last edited by fastslz on 2008-1-4 at 11:04 AM ]

I tested according to the code on floor 6, and didn't change it at all

(1) Tested under XP with no issues, can add, but can't add after reaching 9.
(2) Tested under DOS 7.1 and got "General error reading drive F" and won't add.

I will guess and analyze what the reason might be.

F should be your CD - ROM drive letter. The DOS you booted into doesn't have the external command find.com, and the Path variable has %CDROM% or F:\..... At this time, DOS tries to read the directory under the CD - ROM to find find.com, so a general error occurs when reading drive F. That's how it is in pure DOS; no detail can be wrong.

Finally, emphasize again In pure DOS, change the code echo ^%1>A.TXT in building 6 to echo %1>A.TXT

(1) Tested under XP with no problem, can be added, but cannot be added after 9.

Only 9, there is no way, it is the limitation of find.com, because 10 contains 1, if you use sed, there is no such limitation

Thanks! It's really that there is no find.exe command. After adding it, it's OK!

Is there really no way to break through the limit within 10 under dos7.1?

In the DOS usage introduction on the New DOS Era website, there is an introduction to count, a tool for addition calculations, but I don't know where to download it. I didn't find it in the forum.

@echo off
call test2.bat 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
:start1
if "%1"=="" goto end
sed -n "/%1/p" A.TXT>nul
if not errorlevel 1 if errorlevel 0 goto xxx
shift
goto start1
:end

:xxx
shift
echo %1>A.TXT

:end

The pure DOS version of sed is available on my Google forum. Click my signature link.
Sed usage http://sed.sourceforge.net/sed1line_zh-CN.html