diff --git a/GNUmakefile b/GNUmakefile
new file mode 100644
index 000000000..6f6f1bf82
--- /dev/null
+++ b/GNUmakefile
@@ -0,0 +1,13 @@
+NPX?=	npx
+PRETTIER?=	$(NPX) prettier
+
+.PHONY: all
+all:
+
+.PHONY: fmt
+fmt:
+	$(PRETTIER) --write --prose-wrap always controls/**/*.md
+
+.PHONY: fmt-check
+fmt-check:
+	$(PRETTIER) --check --prose-wrap always controls/**/*.md