diff --git a/src/serial.sh b/src/serial.sh
index 1c5d1fd..2017828 100644
--- a/src/serial.sh
+++ b/src/serial.sh
@@ -67,7 +67,7 @@ else
   SERIAL_OPTS="-serial mon:stdio"
 fi
 
-SERIAL_OPTS="$SERIAL_OPTS \
+SERIAL_OPTS+=" \
         -device virtio-serial-pci,id=virtio-serial0,bus=pcie.0,addr=0x3 \
         -chardev socket,id=charchannel0,host=127.0.0.1,port=12345,reconnect=10 \
         -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=vchannel"