Groups
Group browsing lets you navigate the catalog like a folder tree: pick a metadata field as the "grouper" and each distinct value becomes a folder. It is a mode of the Library screen, not a separate section — inside a folder you get the same columns and actions as the normal listing.
A folder's scope is exact equality (the "Jane Austen" folder contains only
author = 'Jane Austen'), unlike search, which is substring. author is a
single column (a book falls in one folder); tags is many-to-many (a book can
appear in several folders).
CLI
cdx groups --by author
cdx groups --by tag
cdx groups --by rating
cdx groups --by publisher
cdx groups --by language
cdx groups --by series
cdx groups --by format
cdx groups --by author --json
Each row is a value plus its book count. In --json (JSONL, one object per
group), the catch-all group — no author / no tags / no rating — has value: null. An empty catalog prints nothing in --json.
In the TUI
Press g in the Library to open the grouper selector (Author / Tags / Rating /
Publisher / Language / Series / Format / Off). The folder level lists value +
count; Enter drills in. A breadcrumb shows the current group. Esc steps back
one layer at a time: clear the filter → back to folders → leave grouping → back
to the welcome screen. / inside a folder filters that folder's books in memory
without widening its exact scope.