Makefile help generator

Makefile

.PHONY: help
.DEFAULT_GOAL := help

# Show help
help:
	@echo ""
	@echo "Usage:"
	@echo "    make [target]"
	@echo ""
	@echo "Targets:"
	@awk '/^[a-zA-Z\-_0-9]+:/ \
	{ \
		helpMessage = match(lastLine, /^# (.*)/); \
		if (helpMessage) { \
			helpCommand = substr($$1, 0, index($$1, ":")-1); \
			helpMessage = substr(lastLine, RSTART + 2, RLENGTH); \
			printf "\033[36m%-22s\033[0m %s\n", helpCommand,helpMessage; \
		} \
	} { lastLine = $$0 }' $(MAKEFILE_LIST)

When you run make help from the command line, the target performs the following actions:

1. Prints basic usage information, such as make [target].
2. Uses the awk command to read the Makefile and find all lines that start with a letter, number, hyphen, or underscore and end with a colon. These lines represent targets defined in the Makefile.
3. For each target found, the awk command checks if the line above it starts with a #. If it does, it assumes that line contains help information for that target.
4. If help information is found, it uses the printf command to print the target name and help information.

This way, you can add help information for each target in your Makefile, and then use the make help command to automatically generate a help document.