diff --git a/src/extrules.am b/src/extrules.am
index 5218907dc..e0a8f699f 100644
--- a/src/extrules.am
+++ b/src/extrules.am
@@ -36,7 +36,7 @@ grib_yacc.h grib_yacc.c : griby.y
 	rm -f y.tab.c y.tab.h
 
 hash_keys:
-	./make_hash_keys.ksh
+	./make_hash_keys.sh
 
 grib_accessor_classes_hash.c:
 	./make_accessor_class_hash.ksh
diff --git a/src/make_hash_keys.ksh b/src/make_hash_keys.sh
similarity index 100%
rename from src/make_hash_keys.ksh
rename to src/make_hash_keys.sh