Index: lldb/source/Commands/CommandObjectMemory.cpp
===================================================================
--- lldb/source/Commands/CommandObjectMemory.cpp
+++ lldb/source/Commands/CommandObjectMemory.cpp
@@ -767,10 +767,11 @@
     std::string path = outfile_spec.GetPath();
     if (outfile_spec) {
 
-      auto open_options = File::eOpenOptionWrite | File::eOpenOptionCanCreate;
+      File::OpenOptions open_options =
+          File::eOpenOptionWrite | File::eOpenOptionCanCreate;
       const bool append = m_outfile_options.GetAppend().GetCurrentValue();
-      if (append)
-        open_options |= File::eOpenOptionAppend;
+      open_options |=
+          append ? File::eOpenOptionAppend : File::eOpenOptionTruncate;
 
       auto outfile = FileSystem::Instance().Open(outfile_spec, open_options);
 
Index: lldb/test/API/functionalities/memory/read/TestMemoryRead.py
===================================================================
--- lldb/test/API/functionalities/memory/read/TestMemoryRead.py
+++ lldb/test/API/functionalities/memory/read/TestMemoryRead.py
@@ -2,11 +2,12 @@
 Test the 'memory read' command.
 """
 
-
-
 import lldb
-from lldbsuite.test.lldbtest import *
 import lldbsuite.test.lldbutil as lldbutil
+import tempfile
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
 
 
 class MemoryReadTestCase(TestBase):
@@ -19,27 +20,34 @@
         # Find the line number to break inside main().
         self.line = line_number('main.cpp', '// Set break point at this line.')
 
-    def test_memory_read(self):
-        """Test the 'memory read' command with plain and vector formats."""
+    def build_run_stop(self):
         self.build()
         exe = self.getBuildArtifact("a.out")
         self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)
 
         # Break in main() after the variables are assigned values.
-        lldbutil.run_break_set_by_file_and_line(
-            self, "main.cpp", self.line, num_expected_locations=1, loc_exact=True)
+        lldbutil.run_break_set_by_file_and_line(self,
+                                                "main.cpp",
+                                                self.line,
+                                                num_expected_locations=1,
+                                                loc_exact=True)
 
         self.runCmd("run", RUN_SUCCEEDED)
 
         # The stop reason of the thread should be breakpoint.
-        self.expect("thread list", STOPPED_DUE_TO_BREAKPOINT,
+        self.expect("thread list",
+                    STOPPED_DUE_TO_BREAKPOINT,
                     substrs=['stopped', 'stop reason = breakpoint'])
 
         # The breakpoint should have a hit count of 1.
-        self.expect("breakpoint list -f", BREAKPOINT_HIT_ONCE,
+        self.expect("breakpoint list -f",
+                    BREAKPOINT_HIT_ONCE,
                     substrs=[' resolved, hit count = 1'])
 
-        # Test the memory read commands.
+    @no_debug_info_test
+    def test_memory_read(self):
+        """Test the 'memory read' command with plain and vector formats."""
+        self.build_run_stop()
 
         # (lldb) memory read -f d -c 1 `&argc`
         # 0x7fff5fbff9a0: 1
@@ -131,3 +139,42 @@
           for o in objects_read:
               self.assertEqual(len(o), expected_object_length)
           self.assertEquals(len(objects_read), 4)
+
+    @no_debug_info_test
+    def test_memory_read_file(self):
+        self.build_run_stop()
+        cmd = "memory read -f d -c 1 `&argc`"
+        res = lldb.SBCommandReturnObject()
+        self.ci.HandleCommand(cmd, res)
+        self.assertTrue(res.Succeeded())
+
+        # Record golden output.
+        golden_output = res.GetOutput()
+
+        temp_file = tempfile.NamedTemporaryFile().name
+
+        def check_file_content(expected):
+            with open(temp_file) as f:
+                lines = f.readlines()
+                for i, line in enumerate(lines):
+                    expected_line = expected[i].strip()
+                    actual_line = line.strip()
+                    self.assertEqual(
+                        expected_line, actual_line,
+                        "Line {} doesn't match: expected '{}' but got '{}'".
+                        format(i, expected_line, actual_line))
+                self.assertEqual(len(expected), len(lines))
+
+        # Sanity check.
+        self.runCmd("memory read -f d -c 1 -o '{}' `&argc`".format(temp_file))
+        check_file_content([golden_output])
+
+        # Make sure the file is truncated when we run the command again.
+        self.runCmd("memory read -f d -c 1 -o '{}' `&argc`".format(temp_file))
+        check_file_content([golden_output])
+
+        # Make sure the file is appended when we run the command with --append-outfile.
+        self.runCmd(
+            "memory read -f d -c 1 -o '{}' --append-outfile `&argc`".format(
+                temp_file))
+        check_file_content([golden_output, golden_output])