Makefile-demo

This repository is to display some features of Makefiles and test how it works. I learned about most of the concepts used here thanks to @looztra.

It is for learning purposes only.

Prerequisites

fzf is used to create an interactive menu. To install fzf on MacOs:

brew install fzf

Lab

Usage of @

@ in makefile is used to supress printing the command to be run. For instance:

tazminia@laptop:~$ make helloworld
Hi

tazminia@laptop:~$ make helloworld-debug
echo "Hi"
Hi

Now if we look at the code the only difference is the use of @

helloworld:
	@echo "Hi"
helloworld-debug:
	echo "Hi"

Usage of include

include allows to load code from other makefiles. For example:

tazminia@laptop:~$ make helloworld
Hi
tazminia@laptop:~$ make get-python-version
Python 3.9.13

• helloworld is a target in Makefile
• get-python-version is a target in mk/python.mk that was included in Makefile

Usage of PHONY

Consider the following:

tazminia@laptop:~$ make helloworld
Hi
tazminia@laptop:~$ make helloworld
Hi
tazminia@laptop:~$ make foo.txt
Create file named foo.txt
tazminia@laptop:~$ make foo.txt
make: 'foo.txt' is up to date.

Usual targets run based on a file presence. This means that foo.txt will only run if no file named foo.txt is present in the directory.

foo.txt:
	@echo "Create file named foo.txt"
	@touch foo.txt

In our case, the first execution creates the file foo.txt, so any following execution skips this target.

When defined with .PHONY like the target helloworld, make understands that no file is involved regarding this recipe and would run even if a file named helloworld exists.

.PHONY: helloworld ➤
helloworld:
	@echo "Hi"

Interactive menu with fzf

1. When no default target is defined and you run just make with no target, the first target available is called.
2. When a person has never used your makefile, it does not know what can be done with it, unless it reads the code.

So, the idea is:

1. To let the user choose the target to run when no target is defined.
2. Be able to present a list of goals available to the user.

The details on how this is achieved can be found here. If you simply want to test it, just run make.