Guard against use of Unix tools.
diff --git a/.github/workflows/file_format.yml b/.github/workflows/file_format.yml
index d61d634..a8d4ce2 100644
--- a/.github/workflows/file_format.yml
+++ b/.github/workflows/file_format.yml
@@ -18,3 +18,4 @@
       with:
         python-version: '3.x'
     - run: python3 ./run_format_tests.py
+    - run: python3 ./run_shell_checks.py