diff --git a/libcxx/test/libcxx/selftest/sh.cpp/run-error.sh.cpp b/libcxx/test/libcxx/selftest/sh.cpp/run-error.sh.cpp
--- a/libcxx/test/libcxx/selftest/sh.cpp/run-error.sh.cpp
+++ b/libcxx/test/libcxx/selftest/sh.cpp/run-error.sh.cpp
@@ -10,4 +10,4 @@
 
 // Make sure the test DOES NOT pass if it fails to run
 
-// RUN: exit 1
+// RUN: false
diff --git a/libcxx/test/libcxx/selftest/sh.cpp/run-success.sh.cpp b/libcxx/test/libcxx/selftest/sh.cpp/run-success.sh.cpp
--- a/libcxx/test/libcxx/selftest/sh.cpp/run-success.sh.cpp
+++ b/libcxx/test/libcxx/selftest/sh.cpp/run-success.sh.cpp
@@ -8,4 +8,4 @@
 
 // Make sure the test passes if it succeeds to run
 
-// RUN: exit 0
+// RUN: true
diff --git a/libcxx/utils/libcxx/test/format.py b/libcxx/utils/libcxx/test/format.py
--- a/libcxx/utils/libcxx/test/format.py
+++ b/libcxx/utils/libcxx/test/format.py
@@ -64,9 +64,7 @@
 
     # Get the default substitutions
     tmpDir, tmpBase = _getTempPaths(test)
-    useExternalSh = True
-    substitutions = lit.TestRunner.getDefaultSubstitutions(test, tmpDir, tmpBase,
-                                                           normalize_slashes=useExternalSh)
+    substitutions = lit.TestRunner.getDefaultSubstitutions(test, tmpDir, tmpBase)
 
     # Check base substitutions and add the %{build} and %{run} convenience substitutions
     _checkBaseSubstitutions(substitutions)
@@ -305,5 +303,5 @@
             return lit.Test.Result(lit.Test.XFAIL if test.isExpectedToFail() else lit.Test.PASS)
         else:
             _, tmpBase = _getTempPaths(test)
-            useExternalSh = True
+            useExternalSh = False
             return lit.TestRunner._runShTest(test, litConfig, useExternalSh, script, tmpBase)