CP=cp
CPIO=cpio
TAR=tar

all:
	$(MAKE) cpio
	$(MAKE) tar
	$(MAKE) cp

cpio: prep
	(cd 2; find -type f | $(CPIO) -pdm ../1)
	diff -upr 2 1

tar: prep
	(cd 2; $(TAR) cf - . | $(TAR) -C ../1 -xf -)
	diff -upr 2 1

cp: prep
	$(CP) -af 2/d 1
	diff -upr 2 1

prep:
	rm -fr 1 2
	mkdir -p 1/d 2/d
	echo foo > 1/d/1
	ln 1/d/1 1/d/2
	ln 1/d/1 1/d/3
	sleep 1
	echo foo > 2/d/1
	echo bar > 2/d/2
	ln 2/d/2 2/d/3
	ln 2/d/2 2/d/4