1. Compile AsciiDoc Files into a Single HTML File:

Using AsciiDoctor, you can convert all asciidoc files into a single HTML file. The command is:

asciidoctor -b html5 -o output.html input.adoc

Repeat for all asciidoc files and then concatenate them into a single HTML file.

2. Create a CSS File (Optional):

If styling is necessary, create a CSS file and link it within the HTML file.

3. Convert HTML to ePub using Pandoc:

Once you have an HTML file, you can convert it to ePub using Pandoc. The command is:

pandoc output.html -o final.epub

4. Modify Calibre Settings (If Needed):

If you're still considering using Calibre, ensure that the settings match the specific needs of the file you're converting. Sometimes, altering specific input or output settings can resolve conversion issues.