fix https://github.com/Neilpang/acme.sh/issues/2409 (#2430)

dnsapi/dns_he.sh

@@ -134,9 +134,9 @@ _find_zone() {
   _zone_ids=$(echo "$_matches" | _egrep_o "hosted_dns_zoneid=[0-9]*&" | cut -d = -f 2 | tr -d '&')
   _zone_names=$(echo "$_matches" | _egrep_o "name=.*onclick" | cut -d '"' -f 2)
   _debug2 "These are the zones on this HE account:"
-  _debug2 "$_zone_names"
+  _debug2 "_zone_names" "$_zone_names"
   _debug2 "And these are their respective IDs:"
-  _debug2 "$_zone_ids"
+  _debug2 "_zone_ids" "$_zone_ids"
   if [ -z "$_zone_names" ] || [ -z "$_zone_ids" ]; then
     _err "Can not get zone names."
     return 1
@@ -154,10 +154,14 @@ _find_zone() {
 
     _debug "Looking for zone \"${_attempted_zone}\""
 
-    line_num="$(echo "$_zone_names" | grep -n "^$_attempted_zone" | cut -d : -f 1)"
-
+    line_num="$(echo "$_zone_names" | grep -n "^$_attempted_zone\$" | _head_n 1 | cut -d : -f 1)"
+    _debug2 line_num "$line_num"
     if [ "$line_num" ]; then
       _zone_id=$(echo "$_zone_ids" | sed -n "${line_num}p")
+      if [ -z "$_zone_id" ]; then
+        _err "Can not find zone id."
+        return 1
+      fi
       _debug "Found relevant zone \"$_attempted_zone\" with id \"$_zone_id\" - will be used for domain \"$_domain\"."
       return 0
     fi