Advanced Batch-File: Dynamically setting a variable with set /p and redirection

Hey there.

Basically, I have a batch-file, that goes through all model and texture files, saves their absolut path and then passes the gathered pathes to my converter.exe. Currently I do this by appending the path of each input file to a set /p variable, with the output of that variable redirected into a params.txt.

for /f "tokens=*" %%a in ('dir "%MODEL_SRC%" /a:d-h /b') do (
 set /p=-o="%MODEL_DST%\%%a.res" >cvtr_params.txt<nul
 for /f %%b in ('dir "%MODEL_SRC%\%%a\*.obj" /a:-d-h /b') do (
  <nul (set/p=""%MODEL_SRC%\%%a\%%b" ") >>cvtr_params.txt
 )
 for /f "tokens=*" %%c in ('dir "%TEX_SRC%\%%a\*.png" /a:-d-h /b') do (
  <nul (set/p=""%TEX_SRC%\%%a\%%c" ") >>cvtr_params.txt
 )
 start /b /wait "" bin\converter.exe @cvtr_params.txt >nul
)
del cvtr_params.txt

The params.txt would look like this:

-o="ConvertedPath\Ingame.res" "ModelPath\Model1.obj" "ModelPath\Model2.obj" "TexPath\Tex1.png" "TexPath\Tex2.png"

And so on and so forth. And yes, the code HAS to be this complicated for actually appending to the end of the line, not a new line.

Now I thought, that the cvtr_params.txt is unnecessary, and had this approach, which did nearly the same, just not redirecting the "question" of the set /p variable into a params.txt but actually just assigning set /p params to the "question" of set /p z.

setlocal EnableDelayedExpansion
for /f "tokens=*" %%a in ('dir "%MODEL_SRC%" /a:d-h /b') do (
 set /p params=<nul
 set /p z=-o="%MODEL_DST%\%%a.res" <nul
 for /f %%b in ('dir "%MODEL_SRC%\%%a\*.obj" /a:-d-h /b') do (
  <nul (set/p=""%MODEL_SRC%\%%a\%%b" ")
 )
 for /f "tokens=*" %%c in ('dir "%TEX_SRC%\%%a\*.png" /a:-d-h /b') do (
  <nul (set/p=""%TEX_SRC%\%%a\%%c" ")
 )
 st开发者_开发问答art /b /wait "" bin\converter.exe !params!
)
endlocal

But somehow, the !params! variable appears as empty. (an echo delivers "ECHO is set to <OFF>") Now I'm at the end of my wits, and I just started seriously working with batch files like 3 days ago, so if anyone has a good idea, let me hear it! :)

Greetz

In your code, params is set to be empty at the beginning and never changed afterwards, so what do you expect?

If you want to concat elements in params, you should try something along the lines of

set params=!params! ""%TEX_SRC%\%%a\%%c" "

but beware, environment variables have a maximum length of 8191 characters since WinXP or later (less on earlier systems).