• dependencies exist between files, e.g.
  • main.o depends on main.c and Stack.h
• actions state how to produce targets from sources, e.g.
  • can create main.o from main.c and Stack.h using gcc
• rules combine dependencies and actions
  • if main.c or Stack.h changes, rebuild main.o with gcc

The  make  command uses a Makefile to rebuild a system