diff --git a/.github/workflows/checkformat.yml b/.github/workflows/checkformat.yml
index 0119fc56..06f1f2be 100644
--- a/.github/workflows/checkformat.yml
+++ b/.github/workflows/checkformat.yml
@@ -16,4 +16,4 @@ jobs:
       - name: Check format
         run: |
           sudo apt install clang-format
-          contrib/checkformat.bash
+          contrib/checkformat.sh
diff --git a/contrib/checkformat.bash b/contrib/checkformat.sh
similarity index 66%
rename from contrib/checkformat.bash
rename to contrib/checkformat.sh
index bcf11b1a..7a5e2c8b 100755
--- a/contrib/checkformat.bash
+++ b/contrib/checkformat.sh
@@ -1,10 +1,10 @@
-#!/usr/bin/env bash
+#!/usr/bin/env sh
 
 # SPDX-License-Identifier: MIT
 
 clang-format --version
 
-find . -type f \( -iname '*.hpp' -o -iname '*.cpp' \) -exec clang-format -i {} +
+find . -type f -iname '*.[ch]pp' -exec clang-format -i {} +
 
 if ! git diff-index --quiet HEAD --; then
 	echo 'Unformatted files:'