lstags

The tool provides a command‑line interface and an API for analyzing, synchronizing, and aggregating Docker images across multiple registries. It can list images matching regular‑expression filters, compare local copies with remote digests, and report five possible states such as ABSENT, PRESENT, CHANGED, LOCAL_ONLY, and NOT_FOUND. Users can pull images from public or private registries into a local cache, then optionally re‑push them to another registry, with support for automatic Docker credential discovery or explicit JSON config files.

Typical use cases include consolidating images from external registries into an internal one for faster access, detecting when a tag like “latest” has been re‑pushed, and pre‑fetching images to reduce startup latency. The utility allows specification of multiple repositories, optional tag assumptions, and configurable push path prefixes to control where images are stored in the destination registry.

The software is written in Go, marked as stable, and distributed as a CLI‑available package. It integrates with Docker’s authentication mechanism and can be invoked with simple commands such as `lstags --pull alpine` or with custom push prefixes and repository filters.