diff --git a/commands_test.go b/commands_test.go
index c0cf43e3..88b777a6 100644
--- a/commands_test.go
+++ b/commands_test.go
@@ -585,6 +585,25 @@ c:
 	assertResult(t, expectedOutput, result.Output)
 }
 
+func TestMergeCmd_Multi(t *testing.T) {
+	cmd := getRootCommand()
+	result := runCmd(cmd, "merge -d1 examples/multiple_docs_small.yaml examples/data2.yaml")
+	if result.Error != nil {
+		t.Error(result.Error)
+	}
+	expectedOutput := `a: Easy! as one two three
+---
+a: other
+another:
+  document: here
+c:
+  test: 1
+---
+- 1
+- 2`
+	assertResult(t, expectedOutput, strings.Trim(result.Output, "\n "))
+}
+
 func TestMergeCmd_Error(t *testing.T) {
 	cmd := getRootCommand()
 	result := runCmd(cmd, "merge examples/data1.yaml")
diff --git a/examples/multiple_docs_small.yaml b/examples/multiple_docs_small.yaml
new file mode 100644
index 00000000..86035cce
--- /dev/null
+++ b/examples/multiple_docs_small.yaml
@@ -0,0 +1,7 @@
+a: Easy! as one two three
+---
+another:
+  document: here
+---
+- 1
+- 2
\ No newline at end of file
diff --git a/yq.go b/yq.go
index 359b576c..e12b6e68 100644
--- a/yq.go
+++ b/yq.go
@@ -200,6 +200,7 @@ If overwrite flag is set then existing values will be overwritten using the valu
 	}
 	cmdMerge.PersistentFlags().BoolVarP(&writeInplace, "inplace", "i", false, "update the yaml file inplace")
 	cmdMerge.PersistentFlags().BoolVarP(&overwriteFlag, "overwrite", "x", false, "update the yaml file by overwriting existing values")
+	cmdMerge.PersistentFlags().IntVarP(&docIndex, "doc", "d", 0, "process document index number (0 based)")
 	return cmdMerge
 }