diff --git a/mlir/examples/standalone/standalone-opt/standalone-opt.cpp b/mlir/examples/standalone/standalone-opt/standalone-opt.cpp
--- a/mlir/examples/standalone/standalone-opt/standalone-opt.cpp
+++ b/mlir/examples/standalone/standalone-opt/standalone-opt.cpp
@@ -46,6 +46,11 @@
     llvm::cl::desc("Run the verifier after each transformation pass"),
     llvm::cl::init(true));
 
+static llvm::cl::opt<bool> allowUnregisteredDialects(
+    "allow-unregistered-dialect",
+    llvm::cl::desc("Allow operation with no registered dialects"),
+    llvm::cl::init(false));
+
 static llvm::cl::opt<bool>
     showDialects("show-dialects",
                  llvm::cl::desc("Print the list of registered dialects"),
@@ -91,7 +96,12 @@
     exit(1);
   }
 
-  return failed(mlir::MlirOptMain(output->os(), std::move(file), passPipeline,
-                                  splitInputFile, verifyDiagnostics,
-                                  verifyPasses));
+  if (failed(MlirOptMain(output->os(), std::move(file), passPipeline,
+                         splitInputFile, verifyDiagnostics, verifyPasses,
+                         allowUnregisteredDialects))) {
+    return 1;
+  }
+  // Keep the output file if the invocation of MlirOptMain was successful.
+  output->keep();
+  return 0;
 }
diff --git a/mlir/test/mlir-opt/outputfile.mlir b/mlir/test/mlir-opt/outputfile.mlir
new file mode 100644
--- /dev/null
+++ b/mlir/test/mlir-opt/outputfile.mlir
@@ -0,0 +1,2 @@
+// RUN: mlir-opt %s -o %t
+// RUN: test -f %t
diff --git a/mlir/tools/mlir-opt/mlir-opt.cpp b/mlir/tools/mlir-opt/mlir-opt.cpp
--- a/mlir/tools/mlir-opt/mlir-opt.cpp
+++ b/mlir/tools/mlir-opt/mlir-opt.cpp
@@ -166,7 +166,12 @@
     exit(1);
   }
 
-  return failed(MlirOptMain(output->os(), std::move(file), passPipeline,
-                            splitInputFile, verifyDiagnostics, verifyPasses,
-                            allowUnregisteredDialects));
+  if (failed(MlirOptMain(output->os(), std::move(file), passPipeline,
+                         splitInputFile, verifyDiagnostics, verifyPasses,
+                         allowUnregisteredDialects))) {
+    return 1;
+  }
+  // Keep the output file if the invocation of MlirOptMain was successful.
+  output->keep();
+  return 0;
 }