# Garbage Collector Roots

The roots of the garbage collector are all store paths to which there are symlinks in the directory ``prefix`/nix/var/nix/gcroots`. For instance, the following command makes the path `/nix/store/d718ef...-foo` a root of the collector:

    $ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar

That is, after this command, the garbage collector will not remove `/nix/store/d718ef...-foo` or any of its dependencies.

Subdirectories of ``prefix`/nix/var/nix/gcroots` are also searched for symlinks. Symlinks to non-store paths are followed and searched for roots, but symlinks to non-store paths inside the paths reached in that way are not followed to prevent infinite recursion.