Packages that are installed but not used may be garbage-collected. The guix-gc command allows users to explicitly run the garbage collector to reclaim space from the /nix/store directory.
The garbage collector has a set of known roots: any file under /nix/store reachable from a root is considered live and cannot be deleted; any other file is considered dead and may be deleted. The set of garbage collector roots includes default user profiles, and may be augmented with guix-build --root, for example (see Invoking guix-build).
The guix-gc command has three modes of operation: it can be
used to garbage-collect any dead files (the default), to delete specific
--delete option), or to print garbage-collector
information. The available options are listed below:
When min is given, stop once min bytes have been collected.
min may be a number of bytes, or it may include a unit as a
suffix, such as
MiB for mebibytes and
GB for gigabytes.
When min is omitted, collect all the garbage.