The make utility automatically determines which pieces of a large program need to be recompiled. To prepare to use make, you must write a file called the makefile that describes the relationships among files in your program and provides commands for updating each file.

target: prerequisites
	recipse
	...
	...

target: can be the generated file or action like "clean"

prerequisites: is the input used to generate the target.

recipe: actions "commands" needs to carry out.

"#" in a line of a makefile starts a comment.

1. GNU Make Manual [https://www.gnu.org/software/make/manual/]
2. Kyle Loudon. 1999. Mastering Algorithms with C (1st. ed.). O'Reilly Media, Inc.