Getting started with GNU make
Make utility comes in handy while working over large projects, where you might have to keep track of compiling different files differently after modifications, since compiling the whole project takes too long (or has a long cryptic command you don't want to keep entering). In such projects, make can simply things by a great amount.
Make determines automatically which pieces of a large program need to be recompiled, and issues the commands to recompile them.
A standard complete reference for make can be found here: GNU make manual
If you are a beginner and looking to get started, you might want to follow up this simple article, which takes you through make in short A short introduction to GNU make