nix-darwin: make several changes to home and system configuration specific to darwin platform

home/frank.nix

@@ -17,6 +17,30 @@ in
       '';
     };
 
+    # Configure ZSH if using darwin (macOS).
+    zsh =
+      if pkgs.stdenv.hostPlatform.isDarwin then
+        {
+          enable = true;
+
+          initExtra = ''
+            clear;fastfetch
+          '';
+        }
+      else
+        { };
+
+    starship = {
+      enable = true;
+
+      settings = {
+        character = {
+          success_symbol = "[λ](bold green)";
+          error_symbol = "[λ](bold red)";
+        };
+      };
+    };
+
     fastfetch = {
       enable = true;
 
@@ -43,7 +67,7 @@ in
         ];
 
         logo = {
-          source = "nixos2";
+          source = if pkgs.stdenv.hostPlatform.isDarwin then "macos" else "nixos2";
         };
       };
     };