anchor.diff:  
         environment.etc."tmux.conf".text = ''
           source-file ${config.system.build.setTmuxOptions}
  -
           bind 0 set status
   
           set -g status-bg black
           set -g status-fg white
  +
  +        source-file $HOME/.tmux.conf.local
         '';
   
         launchd.daemons.nix-daemon =
  
positive.code:             "")       return 1 ;;
            esac
          }
        '';
      };
  
  
negative.code:         export PATH=$HOME/.nix-profile/bin:$HOME/.nix-profile/bin''${PATH:+:$PATH}
  
          export NIX_PATH=nixpkgs=$HOME/.nix-defexpr/nixpkgs
  
          # Set up secure multi-user builds: non-root users build through the
          # Nix daemon.
          if [ "$USER" != root -a ! -w /nix/var/nix/db ]; then
              export NIX_REMOTE=daemon
          fi
  
          nixdarwin-rebuild () {
            case $1 in
  