geewiz I suspect there is a relatively easy way to get the data in, I'm not sure you are going to like the results though.
I don't have access to the Windows client for Diarium, but I would expect it to allow pasting of data into a new entry. So how I would approach this is to:
- Open a terminal in the directory containing the Obsidian notes you want imported
- Use the following command to glue the files together:
type *.md > tmpfile.txt
- Then open tmpfile.txt in Notepad or WordPad
- Select all the text (ctrl-a) and copy it (ctrl-c)
- Open the Windows client for Diarium
- And paste it into a new entry (ctrl-v)
If you want anything fancier than that, that's a whole other kettle of fish.