diff --git a/common.sh b/common.sh
index 4682995a71349313fede354d3c461eb50c84d409..f5b11c9a74b67332e27050b5b66a2d812f89f41a 100755
--- a/common.sh
+++ b/common.sh
@@ -59,7 +59,7 @@ function clear_routed_setup_ipv6 {
 
 function delete_neighbor_proxy {
 
-  if [ -z "$EUI64" -z -o "$UPLINK6" ]; then
+  if [ -z "$EUI64" -o -z "$UPLINK6" ]; then
     return
   fi