diff --git a/os/gfile/gfile_z_example_contents_test.go b/os/gfile/gfile_z_example_contents_test.go
index 7f13c6ae5..13e90500c 100644
--- a/os/gfile/gfile_z_example_contents_test.go
+++ b/os/gfile/gfile_z_example_contents_test.go
@@ -101,7 +101,8 @@ func ExamplePutContentsAppend() {
 	// read contents
 	fmt.Println(gfile.GetContents(tempFile))
 
-	// write contents
+	// It creates and append content string into specifies file path.
+	// It automatically creates directory recursively if it does not exist.
 	gfile.PutContentsAppend(tempFile, " append content")
 
 	// read contents
diff --git a/os/gfile/gfile_z_example_replace_test.go b/os/gfile/gfile_z_example_replace_test.go
index d9c6935b7..df4d3a931 100644
--- a/os/gfile/gfile_z_example_replace_test.go
+++ b/os/gfile/gfile_z_example_replace_test.go
@@ -27,6 +27,7 @@ func ExampleReplaceFile() {
 	// read contents
 	fmt.Println(gfile.GetContents(tempFile))
 
+	// It replaces content directly by file path.
 	gfile.ReplaceFile("content", "replace word", tempFile)
 
 	fmt.Println(gfile.GetContents(tempFile))