Index: utils/lit/tests/Inputs/shtest-shell/lit.cfg
===================================================================
--- utils/lit/tests/Inputs/shtest-shell/lit.cfg
+++ utils/lit/tests/Inputs/shtest-shell/lit.cfg
@@ -4,3 +4,4 @@
 config.test_format = lit.formats.ShTest()
 config.test_source_root = None
 config.test_exec_root = None
+config.substitutions.append(('%{python}', sys.executable))
Index: utils/lit/tests/Inputs/shtest-shell/redirects.txt
===================================================================
--- utils/lit/tests/Inputs/shtest-shell/redirects.txt
+++ utils/lit/tests/Inputs/shtest-shell/redirects.txt
@@ -17,13 +17,13 @@
 # Check stderr redirect (2> and 2>>).
 #
 # RUN: echo "not-present" > %t.stderr-write
-# RUN: %S/write-to-stderr.sh 2> %t.stderr-write
+# RUN: %{python} %S/write-to-stderr.py 2> %t.stderr-write
 # RUN: FileCheck --check-prefix=STDERR-WRITE < %t.stderr-write %s
 #
 # STDERR-WRITE-NOT: not-present
 # STDERR-WRITE: a line on stderr
 #
-# RUN: %S/write-to-stderr.sh 2>> %t.stderr-write
+# RUN: %{python} %S/write-to-stderr.py 2>> %t.stderr-write
 # RUN: FileCheck --check-prefix=STDERR-APPEND < %t.stderr-write %s
 #
 # STDERR-APPEND: a line on stderr
@@ -33,7 +33,7 @@
 # Check combined redirect (&>).
 #
 # RUN: echo "not-present" > %t.combined
-# RUN: %S/write-to-stdout-and-stderr.sh &> %t.combined
+# RUN: %{python} %S/write-to-stdout-and-stderr.py &> %t.combined
 # RUN: FileCheck --check-prefix=COMBINED-WRITE < %t.combined %s
 #
 # COMBINED-WRITE-NOT: not-present
Index: utils/lit/tests/Inputs/shtest-shell/write-to-stderr.py
===================================================================
--- /dev/null
+++ utils/lit/tests/Inputs/shtest-shell/write-to-stderr.py
@@ -0,0 +1,6 @@
+#!/usr/bin/env python
+
+import sys
+
+
+sys.stderr.write('a line on stderr\n')
Index: utils/lit/tests/Inputs/shtest-shell/write-to-stderr.sh
===================================================================
--- utils/lit/tests/Inputs/shtest-shell/write-to-stderr.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/bin/sh
-
-echo "a line on stderr" 1>&2
Index: utils/lit/tests/Inputs/shtest-shell/write-to-stdout-and-stderr.py
===================================================================
--- /dev/null
+++ utils/lit/tests/Inputs/shtest-shell/write-to-stdout-and-stderr.py
@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+
+import sys
+
+
+sys.stdout.write('a line on stdout\n')
+sys.stderr.write('a line on stderr\n')
Index: utils/lit/tests/Inputs/shtest-shell/write-to-stdout-and-stderr.sh
===================================================================
--- utils/lit/tests/Inputs/shtest-shell/write-to-stdout-and-stderr.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/bin/sh
-
-echo "a line on stdout"
-echo "a line on stderr" 1>&2