USB storage devices
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Auto-mounting with udisks
udiskie, a udisks2
front-end that allows to manage removable media can be used. To enable automounting, first enable udisks2:

/etc/nixos/configuration.nix
services.udisks2.enable = true;
Next enable udiskie via Home Manager:

~/.config/home-manager/home.nix
services.udiskie = {
enable = true;
settings = {
# workaround for
# https://github.com/nix-community/home-manager/issues/632
program_options = {
# replace with your favorite file manager
file_manager = "${pkgs.nemo-with-extensions}/bin/nemo";
};
};
};
Once the configurations are reflected, USB storage devices will be instantly recognized when inserted without any additional operations needed.
For other solutions, please refer to udisks - ArchWiki or USB storage devices - ArchWiki.