Command line
The digup program inside the app: search the app's index from a terminal, or get results as JSON for scripts.
The helper DigUp uses to index and to search is also a command-line program, digup. It ships inside the app, so there's nothing more to install.
On a Mac it's /Applications/DigUp.app/Contents/Helpers/digup. The Windows and Linux apps carry the same program in their helper folder (with the .deb, /usr/lib/DigUp/helper/digup), though it has had less use from a terminal there.
Search
digup search "payment declined error"
digup search "a dog on the beach" --kind image,video -n 5
digup search "code: retry a failed call with backoff"
digup search "invoice 2047" --json
It searches the app's own index, the same one the panel uses. --json prints the results for scripts and other tools, --kind limits them to kinds (screenshot, image, pdf, doc, audio, video), and -n sets how many. Each search loads the text part of the model first, so the first result takes about half a second.
Other commands
digup statussays what's in the index.digup estimate <folder>says what would be read in a folder and how long its first pass would take, without reading it.digup --helplists everything, including the commands the app itself uses.
search, status and estimate are safe to run while the app runs. Don't run digup index on the app's own index, since the app's helper writes to it too; give it another folder with --index instead.
The index file
The index is a plain SQLite file in DigUp's data folder (where it is). You can open it read-only with any SQLite tool, and keyword search works straight from it, since it's SQLite's full-text search. Searching by meaning needs the model, which is what digup search adds.