nix-collect-garbage

# Name

`nix-collect-garbage` - delete unreachable store paths

# Synopsis

`nix-collect-garbage` [`--delete-old`] [`-d`] [`--delete-older-than` period] [`--max-freed` bytes] [`--dry-run`]

# Description

The command `nix-collect-garbage` is mostly an alias of `nix-store --gc`, that is, it deletes all unreachable paths in the Nix store to clean up your system. However, it provides two additional options: `-d` (`--delete-old`), which deletes all old generations of all profiles in `/nix/var/nix/profiles` by invoking `nix-env --delete-generations old` on all profiles (of course, this makes rollbacks to previous configurations impossible); and `--delete-older-than` period, where period is a value such as `30d`, which deletes all generations older than the specified number of days in all profiles in `/nix/var/nix/profiles` (except for the generations that were active at that point in time).

# Example

To delete from the Nix store everything that is not used by the current generations of each profile, do

    $ nix-collect-garbage -d