Makefile Odds and Ends

I've recently started using make as a task runner.

It started when I read Mina no Go Gengo (a book on Go) after I began learning Golang. (A revised 2nd edition has since come out!)

I've ended up writing pretty much everything in make lately, and here's a small trick I found useful along the way.

Depending on the task, you might have something that deploys or deletes resources.

For example, say you have a task called serious-task defined like this:

.PHONY: serious-task
serious-task:
	something-serious

Running make serious-task here would directly execute something-serious, but depending on what the task does, you might want to prevent it from running by mistake.

While looking for a good way to handle this, I found the following question:

• Stack Overflow: Making 'make clean' ask for confirmation

Based on this, I defined a task called confirmation like so:

.PHONY: confirmation
confirmation:
	@read -p "Are you serious? [y/N]: " ans && [ $${ans:-N} = y ] || (echo "You're kidding me."; exit 1)

confirmation only exits successfully if it receives a y input.

$ make confirmation
Are you serious? [y/N]: y

$ make confirmation
Are you serious? [y/N]: N
You're kidding me.
make: *** [confirmation] Error 1

From here, all you need to do is call confirmation wherever appropriate:

.PHONY: serious-task
serious-task:
	@$(MAKE) confirmation
	something-serious

$ make serious-task
Are you serious? [y/N]: y
something-serious

$ make serious-task
Are you serious? [y/N]: N
You're kidding me.

Now something-serious only runs when you've explicitly entered y.