SUBDIRS = Lesson1 Lesson2 Lesson3 Lesson4 lesson1 : cd Lesson1; make lesson2 : cd Lesson2; make lesson3 : cd Lesson3; make lesson4 : cd Lesson4; make all: for i in $(SUBDIRS); do pushd $$i && $(MAKE); popd; done clean: for i in $(SUBDIRS); do pushd $$i && $(MAKE) clean; popd; done