nix-collect-garbage remove unreachable store paths nix-collect-garbage --print-live --print-dead The command nix-collect-garbage performs a garbage collection on the Nix store: any paths in the Nix store that are garbage (not reachable from a set of root store expressions) are deleted. The roots of the garbage collector are the store expressions mentioned in the files in the directory prefix/var/nix/gcroots. By default, the roots are all user environments in prefix/var/nix/profiles. You can register other store expressions as roots by writing the full path of the store expression to an arbitrary file in the gcroots directory (or a subdirectory thereof). --print-live / --print-dead These options cause the set of live or dead paths to be printed, respectively, rather than performing an actual garbage collector. They correspond exactly with the sub-operations in nix-store --gc. To delete all unreachable paths, just do: $ nix-collect-garbage