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.