Unix's make(1) program, the original of all these facilities, was designed specifically to help C programmers manage these recipes. It lets you write down the dependencies between files in a project in one or more ‘makefiles’. Each makefile consists of a series of productions ; each one tells make that some given target file depends on some set of source files, and says what to do if any of the sources are newer than the target. You don't actually have to write down all dependencies, as the make program can deduce a lot of the obvious ones from filenames and extensions.

For example: You might put in a makefile that the binary myprog depends on three object files myprog.o, helper.o, and stuff.o. If you have source files myprog.c, helper.c, and stuff.c, make will know without being told that each .o file depends on the corresponding .c file, and supply its own standard recipe for building a .o file from a .c file.

When you run make in a project directory, the make program looks at all productions and timestamps and does the minimum amount of work necessary to make sure derived files are up to date.