diff --git a/clang/tools/clang-format/clang-format-diff.py b/clang/tools/clang-format/clang-format-diff.py
index b25ee8f433751..0a2c24743678d 100755
--- a/clang/tools/clang-format/clang-format-diff.py
+++ b/clang/tools/clang-format/clang-format-diff.py
@@ -25,7 +25,6 @@
 
 import argparse
 import difflib
-import os
 import re
 import subprocess
 import sys
@@ -37,9 +36,8 @@
 
 
 def main():
-    basename = os.path.basename(sys.argv[0])
     parser = argparse.ArgumentParser(
-        description=__doc__.format(clang_format_diff=basename),
+        description=__doc__.format(clang_format_diff="%(prog)s"),
         formatter_class=argparse.RawDescriptionHelpFormatter,
     )
     parser.add_argument(