I can generate a PDF from the online version: Bittle.petoi.com. But as we are still improving the contents, we recommend you check the online version and always export the latest on your end.
Thanks Rongzhong. Is there a way to export/print the whole manual though rather than one section at a time?
I didn't know that you can only export one chapter at a time. You may combine the chapters into one file using some PDF tools, like the preview on Mac.
I did some googling and it seems that it can also be done by some scripts: