Need to convert hundreads of pdf files across several folders. pdf2djvu gui is junk on windows and always crashes after a couple of conversions.

Taking this code of which I am working from

for file in *.pdf; do pdftotext "$file" "$file.txt"; done

I normally run pdf2djvu like this:
pdf2djvu -o *.djvu *.pdf

Using what's below gives me: I Won't write DjVu data to terminal

for file in *.pdf; do pdf2djvu "$file" "$file.djvu"; done

And for:
file in *.pdf; do pdf2djvu -o "$file" "$file.djvu"; done

Unable to load document
PDF error: Couldn't open file*.pdf.djvu: random unknown characters

And for: for file in *.pdf; do "pdf2djvu -o" "$file" "$file.djvu"; done

pdf2djvu -o: command not found

And for: for file in .pdf; do "pdf2djvu -o *.djvu *.pdf" "$file" "$file.djvu"; done
bash: pdf2djvu -o *.djvu *.pdf: No such file or directory