```
[matthew@t480:~]$ nix-env -r
warning: unknown setting 'extra-sandbox-paths'
error: --- UsageError --------------------------------------------------------------------------------------------------------------------------- nix-env
no operation specified
Try 'nix-env --help' for more information.

[matthew@t480:~]$ nix-env -r '.*'
warning: unknown setting 'extra-sandbox-paths'
error: --- UsageError --------------------------------------------------------------------------------------------------------------------------- nix-env
no operation specified
Try 'nix-env --help' for more information.
```