diff --git a/.gitignore b/.gitignore
index 720f634..cbc7adf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@ result
 
 # soonix
 /test.yaml
+/test.json
 # end soonix
diff --git a/lib/lib.nix b/lib/lib.nix
index a1abbff..cf82725 100644
--- a/lib/lib.nix
+++ b/lib/lib.nix
@@ -17,10 +17,10 @@
 
       autogeneratedMessage =
         {
-          yaml = "# Generated by soonix, DO NOT EDIT";
-          toml = "# Generated by soonix, DO NOT EDIT";
-          lua = "--- Generated by soonix, DO NOT EDIT";
-          xml = "<!-- Generated by soonix, DO NOT EDIT -->";
+          yaml = "# Generated by soonix, DO NOT EDIT\n";
+          toml = "# Generated by soonix, DO NOT EDIT\n";
+          lua = "--- Generated by soonix, DO NOT EDIT\n";
+          xml = "<!-- Generated by soonix, DO NOT EDIT -->\n";
         }.${
           format
         } or "";
@@ -31,7 +31,7 @@
           ''
             ${pre.buildCommand}
             cp $out tmp
-            cat <(echo "${autogeneratedMessage}") tmp > $out
+            cat <(echo -n "${autogeneratedMessage}") tmp > $out
           '';
       });
 
diff --git a/nix/repo/soonix.nix b/nix/repo/soonix.nix
index 7983897..83882a7 100644
--- a/nix/repo/soonix.nix
+++ b/nix/repo/soonix.nix
@@ -22,5 +22,14 @@ in
           gitignore = true;
         };
       };
+      testJson = {
+        output = "test.json";
+        data.hello = "world";
+        opts.format = "json";
+        hook = {
+          mode = "copy";
+          gitignore = true;
+        };
+      };
     };
   }).config