diff --git a/bootstrap.sh b/bootstrap.sh
index f5d5c4e..59e0007 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -13,9 +13,9 @@
 for subdir in ${subdirs}; do 
     if [ -x "${subdir}/bootstrap.sh" ]; then 
 	cwd="`pwd`"
-	cd ${subdir}
+	cd "${subdir}"
 	./bootstrap.sh
-	cd ${cwd}
+	cd "${cwd}"
     fi
 done
 
diff --git a/cleanup.sh b/cleanup.sh
index a922b1b..c78c3fc 100755
--- a/cleanup.sh
+++ b/cleanup.sh
@@ -33,8 +33,8 @@
 for subdir in ${subdirs}; do 
     if [ -x "${subdir}/cleanup.sh" ]; then 
 	cwd="`pwd`"
-	cd ${subdir}
+	cd "${subdir}"
 	./cleanup.sh
-	cd ${cwd}
+	cd "${cwd}"
     fi
 done