Recursive makefiles

Another feature of make concerns the environment and recursive invocations. For testing purposes, if make -n is used all actions are printed, including output from lower-level invocations of make. This command prints out the commands that make issues without actually taking the time to execute them.

If the sequence ($MAKE) appears anywhere in a shell-command line, the line is executed even if the -n flag is set. Because the -n flag is exported across invocations of make (through the MAKEFLAGS variable), the only thing that is executed is the make command itself. This feature is useful when a hierarchy of makefile(s) describes a set of software subsystems.