Merge pull request #1177 from pi-hole/fix/validation

Fix CLI domain validation

advanced/Scripts/list.sh

@@ -66,7 +66,7 @@ HandleOther(){
 	domain=$(sed -e "y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/" <<< "$1")
 
 	#check validity of domain
-	validDomain=$(perl -ne 'print if /^(?!.*[^a-z0-9-\.].*)\b((?=[a-z0-9-]{1,63}\.)(xn--)?[a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,63}\b/' <<< "$domain")
+	validDomain=$(echo "${domain}" | grep -P '^(?!.*[^a-z0-9-\.].*)\b((?=[a-z0-9-]{1,63}\.)(xn--)?[a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,63}\b')
 	if [ -z "${validDomain}" ]; then
 		echo "::: $1 is not a valid argument or domain name"
 	else