China DOS Union

Thanks

I have a question about a batch file and would like to ask everyone.
> 1. if not exist c:\ucdos.bat goto win98
> ......
> etx cl198
> :wing98
> ......
> Among them: what does this line mean, etx cl198?
>
> 2. pause > nul
>
> Question: I remember that "pause" alone is enough for pausing. What does the following ">nul" mean?
>
> 3. mdir c:\ah /m /f5000000
> if errorlevel 1 goto inset1
> goto help
> :inset1
> ......
> Question: what do the last 2 parameters of the command that creates directory AH mean? What error is line 2 testing for, and is line 3 jumping
to the HELP section? I couldn't find the start of HELP in the whole batch file.
>
> 4. In a batch file, can .TXT and .xls documents be opened just like running .COM and .BAT?
> 5. In a batch file, is it possible to test whether a hard disk partition exists? Like in #1 where it tests whether a specified file exists, for example before executing
MD F：\HYQ, first test whether F exists?
> 6. Before I execute (by default) MD F：\HYQ, I want to give the user a prompt so the user can specify the directory
name, and then use that directory name in the following commands. It's a bit like entering a string from the keyboard in C. Can this be done in a batch file? How do I write it?

Especially questions 5 and 6?

Why is nobody here???????????????

This is a *.bat file I wrote by copying the example in a book, but it gives an error when run.
Please help me take a look


@echo off
choice /c:mde mem,defrag,end
if errorlevel 3 goto mem（you should test the highest error code value first）
if errorlevel 2 goto defrag
if errotlevel 1 goto end

:mem
mem
goto end
:defrag
c:\windows\defrag.exe
goto end
:end
echo good bye

@echo off
choice /c:mde mem,defrag,end
if errorlevel 3 goto end（you should test the highest error code value first）
if errorlevel 2 goto defrag
if errotlevel 1 goto mem
:mem
mem
goto end
:defrag
c:\windows\defrag.exe
goto end
:end
echo good bye

The following is quoted from iceboy's post on 2003-10-6 15:42:54:
Yes! The simplest method is to use Choice.com; if you want something more complicated, use Menustar or ChoiceX, or just write a small program too.

We found that all of you have gotten the CHOICE method wrong!!! If something goes wrong, I won't take responsibility
@echo off
f:\pillow\dos\tw.exe
set path=f:\pillow\dos;e:\ghost
echo.
echo MS-DOS 7.10 boot menu
echo.
echo 1. Boot to DOS
echo 2. Back up system
echo 3. Restore system
echo.
choice /c:123 /n /t:1,30 Please choose:
if errorlevel 3 goto DOS
if errorlevel 2 goto BACKUP
if errorlevel 1 goto RESTORE
OS
goto exit
:BACKUP
ghost -clone,mode=pdump,src=1:1,dst=e:\ghost\win2k_1.gh1 -fx -rb
goto exit
:RESTORE
ghost -clone,mode=pload,src=e:\ghost\win2000.gh1,dst=1:1 -rb
:exit

set LglDrv=27 * 26 Z 25 Y 24 X 23 W 22 V 21 U 20 T 19 S 18 R 17 Q 16 P 15
set LglDrv=%LglDrv% O 14 N 13 M 12 L 11 K 10 J 9 I 8 H 7 G 6 F 5 E 4 D 3 CThe meaning above is to assign all the characters after the equals sign "=" to the variable %LglDrv%.

This post is really great and very valuable as a reference. It ought to be moved to the front, bump!!!

Verifying the "Godd Bach" conjecture (please add odd numbers)

:: Solve.bat - program for verifying Goldbach's conjecture

:: Will Sort - 2004/11/18

::

:: Modified from a prime-number piling program

:: Environment variable notes:

::   iTest: test number, iPrime: prime number index

::   divisor: divisor used to test primes, iDivisor: divisor index

::   Factor1&Factor2: the two factors of the even number, iFactor1&iFicator2: factor indices

::   less: marker for not enough to divide in division, diff: marker for a difference value in subtraction

::

@echo off

if == goto %2

if == %comspec% /e:4096 /c %0 $ init

del ~Solve.bat

goto end



:: Initialization: generate prime 2, store it as the first prime, set the loop starting value to 3

:init

set iTest=I I

set iPrime=I

set %iPrime%=I I



:: For odd numbers %iTest% from 3~n, divide them by all generated primes from small to large in a loop

:: If none divide evenly then store %iTest% as prime %iPrime%, otherwise jump to Solve

:: Decompose each even number %iTest% from 3~n into the sum of two generated primes

:: If decomposed exactly then display this even number and the two factors, otherwise continue looping MainLoop

:MainLoop

rime - test whether an odd number is prime

set iTest=I %iTest%

set iDivisor=I

    rimeLoop

    echo set divisor=%%%iDivisor%%%>~Solve.bat

    call ~Solve.bat

    call %0 $ Divide %iTest%

    if "%less%"=="" goto Solve

    if "%iDivisor%"=="%iPrime%" goto IsPrime

    set iDivisor=I%iDivisor%

    goto PrimeLoop

:IsPrime

set iPrime=I%iPrime%

set %iPrime%=%iTest%

:Solve - decompose an even number into the sum of primes

set iTest=I %iTest%

set iFactor1=

    :SolveLoop

    set iFactor1=I%iFactor1%

    if "%iFactor1%"=="I%iPrime%" goto SolveLoop

    set iFactor2=%iFactor1%

        :SolveSubLoop

        if "%iFactor2%"=="I%iPrime%" goto SolveLoop

        echo set Factor1=%%%iFactor1%%%> ~Solve.bat

        echo set Factor2=%%%iFactor2%%%>>~Solve.bat

        call ~Solve.bat

        call %0 $ Minus %iTest%

        if "%diff%"=="" goto IsSolve

        set iFactor2=I%iFactor2%

        goto SolveSubLoop

:IsSolve

echo %iTest%

echo %Factor1% + %Factor2%

if "%iPrime%"=="IIIIIIIII" goto end

goto MainLoop



:: Divide the passed dividend %iTest% by the divisor %divisor% (repeated subtraction)

:: If it is not enough to divide (cannot divide evenly) then return the not-enough signal less, otherwise return directly

ivide

for %%n in (%divisor%) do shift

if not == goto Divide

set less=

if == set less=true

goto end



:: Subtract the subtrahends %Factor1% and %Factor2% from the passed minuend %iTest%

:: If there is a difference left (cannot be decomposed) then return the difference signal diff, otherwise return directly

:Minus

for %%n in (%Factor1%) do shift

for %%n in (%Factor2%) do shift

set diff=

if "%2"=="" set diff=true

if not "%3"=="" set diff=true

goto end



:end

I got it, but I can't understand it

Use 【code】【/code】 (the English ones; right now I can only write them in Chinese) to enter indented text

If you want to ask, go find willsort. She's very familiar with this, a batch file expert