nix auto-updating system with flakes

provision.sh

#!/usr/bin/env bash

set -euo pipefail

readonly flake_name='u3macbook'

readonly real_script_dir=$( dirname $(readlink $HOME/.config/nixpkgs/flake.nix) )

header() {
  local -r msg="${1:-}"
  echo '--------------------------------------------------------------------------------'
  echo "> ${msg}"
  echo '--------------------------------------------------------------------------------'
}

footer() {
  echo
}

main() {
  header 'brew upgrade'
    brew upgrade
  footer

  header 'home-manager switch'
    nix flake update "${real_script_dir}"
    home-manager switch --flake path:$real_script_dir#$flake_name
  footer

  header 'home-manager expire-generations "-30 days"'
    home-manager expire-generations '-30 days'
  footer

  echo '> Done.'
}

main