nix profile
    --help
    install nixpkgs#hello
    list
    update hello
    remove hello

If you’re already familiar with Nix, this is a replacement for nix-env.

~/.nix-profile@
    -> ~/.local/state/nix/profiles/profile

~/.nix-defexpr/channels

?
~/.nix-profile/
    manifest.json

2021
https://serokell.io/blog/practical-nix-flakes
    ~/.config/nix/nix.conf