diff --git a/build.sh b/build.sh
index 5b745e8..2492a47 100755
--- a/build.sh
+++ b/build.sh
@@ -16,7 +16,8 @@ EOF
 		fi
 		if [ -f ${i}-packages-nr ]; then
 			log "Begin ${SUB_STAGE_DIR}/${i}-packages-nr"
-			PACKAGES=`cat $i-packages-nr | tr '\n' ' '`
+			PACKAGES="$(sed -e ':a;N;$ !b a' -e 's/[[:space:]]*\(#[^\n]*\)*[[:space:]]/ /g' < ${i}-packages-nr)"
+
 			if [ -n "$PACKAGES" ]; then
 				on_chroot sh -e - << EOF
 apt-get install --no-install-recommends -y $PACKAGES
@@ -26,7 +27,7 @@ EOF
 		fi
 		if [ -f ${i}-packages ]; then
 			log "Begin ${SUB_STAGE_DIR}/${i}-packages"
-			PACKAGES=`cat $i-packages | tr '\n' ' '`
+			PACKAGES="$(sed -e ':a;N;$ !b a' -e 's/[[:space:]]*\(#[^\n]*\)*[[:space:]]/ /g' < ${i}-packages)"
 			if [ -n "$PACKAGES" ]; then
 				on_chroot sh -e - << EOF
 apt-get install -y $PACKAGES