anchor.diff:        '';
       };
   
  +    changeDirWidgetCommand = mkOption {
  +      type = types.nullOr types.str;
  +      default = null;
  +      example = "fd --type d" ;
  +      description = ''
  +        The command that gets executed as the source for fzf for the
  +        ALT-C keybinding.
  +      '';
  +    };
  +
       changeDirWidgetOptions = mkOption {
         type = types.listOf types.str;
         default = [];
         example = [ "--preview 'tree -C {} | head -200'" ];
         description = ''
           Command line options for the ALT-C keybinding.
  +      '';
  +    };
  +
  +    historyWidgetCommand = mkOption {
  +      type = types.nullOr types.str;
  +      default = null;
  +      description = ''
  +        The command that gets executed as the source for fzf for the
  +        CTRL-R keybinding.
         '';
       };
   
  
positive.code: 
      home.sessionVariables =
        mapAttrs (n: v: toString v) (
          filterAttrs (n: v: v != []) {
            FZF_ALT_C_OPTS = cfg.changeDirWidgetOptions;
            FZF_CTRL_R_OPTS = cfg.historyWidgetOptions;
            FZF_CTRL_T_OPTS = cfg.fileWidgetOptions;
            FZF_DEFAULT_OPTS = cfg.defaultOptions;
          }
        );
  
negative.code:   options.programs.fzf = {
      enable = mkEnableOption "fzf - a command-line fuzzy finder";
  
      defaultCommand = mkOption {
        type = types.nullOr types.str;
        default = null;
        example = "fd --type f";
        description = ''
          The command that gets executed as the default source for fzf
          when running.
        '';
      };
  
      defaultOptions = mkOption {
        type = types.listOf types.str;
        default = [];
        example = [ "--height 40%" "--border" ];
        description = ''
          Extra command line options given to fzf by default.
        '';
      };
  
      fileWidgetCommand = mkOption {
        type = types.nullOr types.str;
        default = null;
        example = "fd --type f";
        description = ''
          The command that gets executed as the source for fzf for the
          CTRL-T keybinding.
        '';
      };
  
  