diff --git a/scripts/check-rules.sh b/scripts/check-rules.sh
index 8788f70..093de16 100755
--- a/scripts/check-rules.sh
+++ b/scripts/check-rules.sh
@@ -87,7 +87,7 @@ if [ -n "$COMPOSE_FILES" ]; then
         # Count top-level service keys (2-space indent under services:) and
         # compare against the number of container_name: declarations.
         svc_count=$(awk '/^services:/{f=1;next} f&&/^[^[:space:]]/{f=0} f&&/^[[:space:]]{2}[[:alnum:]_-]+:[[:space:]]*$/{c++} END{print c+0}' "$cf")
-        cn_count=$(grep -cE '^[[:space:]]*container_name:' "$cf" 2>/dev/null)
+        cn_count=$(grep -cE '^[[:space:]]*container_name:' "$cf" 2>/dev/null || true)
         if [ "${svc_count:-0}" -gt 0 ] && [ "$cn_count" -lt "$svc_count" ]; then
             BAD=$((BAD + 1))
         fi