diff --git a/tools/prettify/prettify_cp2k/normalizeFortranFile.py b/tools/prettify/prettify_cp2k/normalizeFortranFile.py
index cc00cdaea6..e776743b00 100644
--- a/tools/prettify/prettify_cp2k/normalizeFortranFile.py
+++ b/tools/prettify/prettify_cp2k/normalizeFortranFile.py
@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 import sys
 import re
 import logging
diff --git a/tools/prettify/prettify_cp2k/replacer.py b/tools/prettify/prettify_cp2k/replacer.py
index 7bc5ae853d..cbcf48c3fe 100644
--- a/tools/prettify/prettify_cp2k/replacer.py
+++ b/tools/prettify/prettify_cp2k/replacer.py
@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 import re
 import sys
 
diff --git a/tools/prettify/prettify_cp2k/selftest.py b/tools/prettify/prettify_cp2k/selftest.py
index fedc6a594d..f8f29a8e8e 100644
--- a/tools/prettify/prettify_cp2k/selftest.py
+++ b/tools/prettify/prettify_cp2k/selftest.py
@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 content = """
 MODULE prettify_selftest
    IMPLICIT NONE