diff --git a/help/help_diff.sh b/help/help_diff.sh
index 291fe134ad..2e12951a15 100755
--- a/help/help_diff.sh
+++ b/help/help_diff.sh
@@ -6,4 +6,21 @@
 #
 # Example: help_diff.sh help_mp-hu.h < help_mp-en.h > missing.h
 
-sed "`sed '/^#define *[^ ][^ ]* .*$/!d;s@^#define *\([^ ][^ ]*\) .*$@/^#define *\1 /d@' < help_mp-$1.h ; echo '/^#define/!d'`" < help_mp-en.h
+curr=""
+
+while read -r line; do
+	if echo "$line" | grep '^#define' > /dev/null 2>&1; then
+		curr=`printf "%s\n" "$line" | cut -d ' ' -f 2`
+		if grep "^#define $curr[	 ]" $1 > /dev/null 2>&1; then
+			curr=""
+		fi
+	else
+		if [ -z "$line" ]; then
+			curr=""
+		fi
+	fi
+
+	if [ -n "$curr" ]; then
+		printf "%s\n" "$line"
+	fi
+done