diff --git a/ipset/def.sh b/ipset/def.sh
index e26ebc7..28e04aa 100644
--- a/ipset/def.sh
+++ b/ipset/def.sh
@@ -167,7 +167,7 @@ flush_dns_cache()
  fi
 
  # MacOS
- if exists pgrep && pgrep -q ^mDNSResponder$; then
+ if exists pgrep && pgrep ^mDNSResponder$ >/dev/null; then
   killall -HUP mDNSResponder
  fi
 }