2 files changed, 10 insertions, 5 deletions
diff --git a/Makefile b/Makefile
index c43eeda..0fcc468 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,6 @@
 .PHONY: check format check-luacheck check-format
 
-LUA_FILES = $(wildcard *.lua)
-
-# bash's process substitution is used for check-format
-SHELL := /bin/bash
+LUA_FILES := $(wildcard *.lua)
 
 check: check-luacheck check-format
 
@@ -11,7 +8,7 @@ check-luacheck:
 	luacheck --globals=vis -- $(LUA_FILES)
 
 check-format:
-	for f in $(LUA_FILES); do diff $$f <(lua-format $$f) >/dev/null; done
+	for lf in $(LUA_FILES); do tools/check-format "$${lf}"; done
 
 format:
 	lua-format -i $(LUA_FILES)
diff --git a/tools/check-format b/tools/check-format
new file mode 100755
index 0000000..392d023
--- /dev/null
+++ b/tools/check-format
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+LUA_FILE=$1
+lua-format "${LUA_FILE}" > "${LUA_FILE}.fmt"
+diff "${LUA_FILE}" "${LUA_FILE}.fmt"
+RET=$?
+rm "${LUA_FILE}.fmt"
+exit ${RET}