+[ -n "$ARCH" ] && echo "ARCH=$ARCH" > /etc/debootstrap/variables
+[ -n "$GRUB" ] && echo "GRUB=$GRUB" >> /etc/debootstrap/variables
+[ -n "$GROOT" ] && echo "GROOT=$GROOT" >> /etc/debootstrap/variables
+[ -n "$TARGET" ] && echo "TARGET=$TARGET" >> /etc/debootstrap/variables
+[ -n "$MIRROR" ] && echo "MIRROR=$MIRROR" >> /etc/debootstrap/variables
+[ -n "$CHROOTMIRROR" ] && echo "CHROOTMIRROR=$CHROOTMIRROR" >> /etc/debootstrap/variables