nix-store
Manipulate or query the Nix store.
TLDR
Collect garbage, such as removing unused paths
$ nix-store --gc
Hard-link identical files together to reduce space usage
$ nix-store --optimise
Delete a specific store path (must be unused)
$ nix-store --delete [/nix/store/...]
Show all dependencies of a store path (package), in a tree format
$ nix-store --query --tree [/nix/store/...]
Calculate the total size of a certain store path with all the dependencies
$ du -cLsh $(nix-store --query --references [/nix/store/...])
Show all dependents of a particular store path
$ nix-store --query --referrers [/nix/store/...]
