diff --git a/CppCoreGuidelines.md b/CppCoreGuidelines.md
index f2dfa0b..0ef3e3b 100644
--- a/CppCoreGuidelines.md
+++ b/CppCoreGuidelines.md
@@ -5531,7 +5531,7 @@ It's a standard-library requirement.
 ##### Example, bad
 
     template<>
-    struct hash<My_type> {	// thoroughly bad hash specialization
+    struct hash<My_type> {  // thoroughly bad hash specialization
         using result_type = size_t;
         using argument_type = My_type;
 
@@ -14333,7 +14333,7 @@ The names are mostly ISO standard-library style (lower case and underscore):
 
 * `T*`      // The `T*` is not an owner, may be null; assumed to be pointing to a single element.
 * `char*`   // A C-style string (a zero-terminated array of characters); may be null.
-* `const char*` 	// A C-style string; may be null.
+* `const char*`  // A C-style string; may be null.
 * `T&`      // The `T&` is not an owner and can never be a "null reference"; references are always bound to objects.
 
 The "raw-pointer" notation (e.g. `int*`) is assumed to have its most common meaning; that is, a pointer points to an object, but does not own it.
diff --git a/scripts/Makefile b/scripts/Makefile
index e1e569d..527b588 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -15,7 +15,8 @@ default: all
 .PHONY: all
 all: \
 check-markdown \
-check-references
+check-references \
+check-notabs
 
 
 $(BUILD_DIR):
@@ -57,6 +58,14 @@ check-references: $(SOURCEPATH) $(BUILD_DIR) Makefile
 ## check if output has data
 	if [ -s "build/CppCoreGuidelines.md.uniq" ]; then echo 'Found duplicate anchors:'; cat $(BUILD_DIR)/$(SOURCEFILE).uniq; false; fi
 
+.PHONY: check-notabs
+check-notabs: $(SOURCEPATH) $(BUILD_DIR) Makefile
+# find lines with tabs
+# old file still might be around
+	rm -f $(BUILD_DIR)/CppCoreGuidelines.md.tabs
+# print file, add line numbers, remove tabs from nl tool, grep for remaining tabs, replace with stars
+	cat ../CppCoreGuidelines.md | nl -ba | sed -s 's/\(^[^\t]*\)\t/\1--/g' | grep -P '\t' | sed -s 's/\t/\*\*\*\*/g' > $(BUILD_DIR)/CppCoreGuidelines.md.tabs
+	if [ -s $(BUILD_DIR)/CppCoreGuidelines.md.tabs ]; then echo 'Warning: Tabs found:'; cat $(BUILD_DIR)/CppCoreGuidelines.md.tabs; false; fi;
 
 #### install npm modules
 # install/update npm dependencies defined in file package.json