diff -Naur a/Makefile b/Makefile
--- a/Makefile	2014-04-18 17:35:39.000000000 +0000
+++ b/Makefile	2015-10-29 02:08:30.660000000 +0000
@@ -95,12 +95,12 @@
 	rm -f *~
 
 install: tree
-	install -d $(BINDIR)
-	install -d $(MANDIR)
+	install -d $(DESTDIR)$(BINDIR)
+	install -d $(DESTDIR)$(MANDIR)
 	if [ -e $(TREE_DEST) ]; then \
-		install $(TREE_DEST) $(BINDIR)/$(TREE_DEST); \
+		install $(TREE_DEST) $(DESTDIR)$(BINDIR)/$(TREE_DEST); \
 	fi
-	install doc/$(MAN) $(MANDIR)/$(MAN)
+	install doc/$(MAN) $(DESTDIR)$(MANDIR)/$(MAN)
 
 distclean:
 	if [ -f tree.o ]; then rm *.o; fi