anchor.diff:      '';
   
       envExtra = ''
  -      source /etc/profile.d/nix.sh
  +      (( $+commands[nix] )) || source /etc/profile.d/nix.sh
       '';
   
       initExtraBeforeCompInit = ''
  
positive.code:     pkgs.nixfmt
      pkgs.tree
      pkgs.nix-tree
  
      # cloud
      pkgs.aws-vault
  
negative.code:     # java
      pkgs.jdk11
  
      # misc
      pkgs.consul
    ];
  
    # Let Home Manager install and manage itself.
    programs.home-manager.enable = true;
  
    programs.direnv.enable = true;
    programs.direnv.enableNixDirenvIntegration = true;
  