Test makefile playground

Makefile

HELLO_FILE_NAME := ".hello"

tidy-hello:
	-rm $(HELLO_FILE_NAME)

save-hello: tidy-hello write-to-hello

write-to-hello:
	echo "save this hello" > $(HELLO_FILE_NAME)

smoke:
	@echo "BASH_HELLO: $$BASH_HELLO"
	@echo "SHELL_HELLO: $$SHELL_HELLO" # This is empty the first time it is run

hello:
	$(MAKE) save-hello

	BASH_HELLO="$$(cat $(HELLO_FILE_NAME))" \
	SHELL_HELLO="$(shell cat $(HELLO_FILE_NAME))" \
		$(MAKE) smoke