note makefile help

system/Makefiles.md

@@ -183,3 +183,5 @@ In this case, the makefile can see that `backup` depends on the current backup f
 
 - [File patterns](Makefiles/patterns.md)
 - [Makefile graphs](Makefiles/graph-easy.md)
+- [In-build help](Makefiles/help.md)
+- [Makefile graphs](Makefiles/graph-easy.md)

system/Makefiles/help.md

@@ -0,0 +1,18 @@
+---
+title: "Makefiles"
+tags: [ "system", "makefiles", "help" ]
+---
+
+Make your first target 'help' to give an overview of the main targets.
+Running `make help` will search for text which starts with `## ` and show what that target does.
+
+```make
+help: ## Print the help message
+	@awk 'BEGIN {FS = ":.*?## "} /^[0-9a-zA-Z._-]+:.*?## / {printf "\033[36m%s\033[0m : %s\n", $$1, $$2}' $(MAKEFILE_LIST) | \
+		sort | \
+		column -s ':' -t
+
+clean: ## Remove generated files
+	$(RM) $(defaults)
+```
+