diff --git a/Makefile b/Makefile
index d741498..633e1e3 100644
--- a/Makefile
+++ b/Makefile
@@ -14,13 +14,13 @@ TAR	= tar -czvf
 all: subdirs
 
 subdirs:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE)) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE)) || exit; done
 
 clean:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) clean) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) clean) || exit; done
 
 distclean:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) distclean) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) distclean) || exit; done
 
 dist:
 	$(RM) -r -- $(PACKAGE)-$(VERSION)
@@ -62,7 +62,7 @@ dist:
 	$(RM) -- $(PACKAGE)-$(VERSION)
 
 install:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) install) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) install) || exit; done
 	$(MKDIR) $(DESTDIR)$(PREFIX)/share/doc/configure
 	$(INSTALL) -m 0644 -- BUGS $(DESTDIR)$(PREFIX)/share/doc/configure/BUGS
 	$(MKDIR) $(DESTDIR)$(PREFIX)/share/doc/configure
@@ -73,7 +73,7 @@ install:
 	$(INSTALL) -m 0644 -- README $(DESTDIR)$(PREFIX)/share/doc/configure/README
 
 uninstall:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) uninstall) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) uninstall) || exit; done
 	$(RM) -- $(DESTDIR)$(PREFIX)/share/doc/configure/BUGS
 	$(RM) -- $(DESTDIR)$(PREFIX)/share/doc/configure/CHANGES
 	$(RM) -- $(DESTDIR)$(PREFIX)/share/doc/configure/INSTALL
diff --git a/doc/Makefile b/doc/Makefile
index c841a87..e2b05f2 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -11,7 +11,7 @@ INSTALL	= install
 all: subdirs $(TARGETS)
 
 subdirs:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE)) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE)) || exit; done
 
 configure.1: configure.xml
 	./docbook.sh -P "$(PREFIX)" -- "configure.1"
@@ -26,25 +26,25 @@ project.conf.html: project.conf.xml
 	./docbook.sh -P "$(PREFIX)" -- "project.conf.html"
 
 clean:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) clean) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) clean) || exit; done
 	$(RM) -- $(configure.1_OBJS) $(configure.html_OBJS) $(project.conf.5_OBJS) $(project.conf.html_OBJS)
 	./docbook.sh -c -P "$(PREFIX)" -- "project.conf.html"
 
 distclean:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) distclean) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) distclean) || exit; done
 	$(RM) -- $(configure.1_OBJS) $(configure.html_OBJS) $(project.conf.5_OBJS) $(project.conf.html_OBJS)
 	./docbook.sh -c -P "$(PREFIX)" -- "project.conf.html"
 	$(RM) -- $(TARGETS)
 
 install: $(TARGETS)
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) install) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) install) || exit; done
 	./docbook.sh -P "$(DESTDIR)$(PREFIX)" -i -- "configure.1"
 	./docbook.sh -P "$(DESTDIR)$(PREFIX)" -i -- "configure.html"
 	./docbook.sh -P "$(DESTDIR)$(PREFIX)" -i -- "project.conf.5"
 	./docbook.sh -P "$(DESTDIR)$(PREFIX)" -i -- "project.conf.html"
 
 uninstall:
-	@for i in $(SUBDIRS); do (cd $$i && $(MAKE) uninstall) || exit; done
+	@for i in $(SUBDIRS); do (cd "$$i" && $(MAKE) uninstall) || exit; done
 	./docbook.sh -P "$(DESTDIR)$(PREFIX)" -u -- "configure.1"
 	./docbook.sh -P "$(DESTDIR)$(PREFIX)" -u -- "configure.html"
 	./docbook.sh -P "$(DESTDIR)$(PREFIX)" -u -- "project.conf.5"