diff --git a/acme.sh b/acme.sh
index 13b1235c..c21f7de4 100755
--- a/acme.sh
+++ b/acme.sh
@@ -4202,7 +4202,7 @@ _process() {
             return 1
           fi
           
-          _sepexis=$(echo "$_dvalue" | grep ",")
+          _sepexis="$(echo "$_dvalue" | grep ",")"
           if [ "$_sepexis" ]; then
             _err "'$_dvalue' is not a valid domain for parameter '$1', please use more command to add domains"
             return 1