Inspired by (and using libraries from) Simon Willison's Dogsheep project. You're probably going to want to run Datasette on the resulting db.

$ pip install pinboard-to-sqlite 

Run:

$ pinboard-to-sqlite auth 

This will direct you to https://pinboard.in/settings/password to find your API token, which you'll then paste into the terminal. This'll get saved in an auth.json file, which subsequent commands will pick up.

To save to a different file, see the -a / --auth flag.

Run:

$ pinboard-to-sqlite posts pinboard.db 

Where pinboard.db is the name of the database you'd like to save posts to. Note that the API this uses has a rate limit of once per minute, so don't run this command more than once per minute (I don't know why you would). This doesn't seem to be enforced fairly loosely, but be careful anyway.