anchor.diff:        pkgs.ripgrep
         pkgs.neovim
         pkgs.nodejs-9_x
  +      pkgs.go
       ];
   
     # Auto upgrade nix package and the daemon service.
  
positive.code:         alias z='fasd_cd -d'     # cd, same functionality as j in autojump
          alias zz='fasd_cd -d -i' # cd with interactive selection
          alias v='f -e vim' # quick opening files with vim
        '';
  
      # environment variables
      variables = {};
    };
  }
  
negative.code:     enableSyntaxHighlighting = true;
      shellInit =
        ''
          # fasd
          alias a='fasd -a'        # any
          alias s='fasd -si'       # show / search / select
          alias d='fasd -d'        # directory
  