There is a clickhouse install, but no uninstall

The single clickhouse binary can install itself with sudo ./clickhouse install and then manage itself with start, stop, status and restart. It cannot undo the install. That bites when a trial box becomes a real deployment and you want the package-manager version or an older one, but the self-installed copy, its registered service and its test data are in the way. I asked for sudo ./clickhouse uninstall. When a maintainer asked why anyone would want that, I listed the reasons: switching to packages, installing an older version, a clean slate, recovering from broken directory permissions, and symmetry.

Nothing has happened. The issue is open, labelled feature, comp-build-system and external, with two comments (the question and my answer) and no assignee.

On 26.4 the subcommand list ends at restart, and running clickhouse uninstall just prints the list of valid subcommands:

clickhouse install [args]
clickhouse start [args]
clickhouse stop [args]
clickhouse status [args]
clickhouse restart [args]

Until it exists, treat clickhouse install as a one-way door: clickhouse stop, then remove by hand what the installer put on the system, and note what it did as it ran. Better, try builds in a throwaway VM or container. For switching versions without a system install, chctl local install/use/remove covers half the wish; see the version-pinning request.