diff --git a/tools/run_webots.sh b/tools/run_webots.sh
index 8c8a759..3263a86 100755
--- a/tools/run_webots.sh
+++ b/tools/run_webots.sh
@@ -115,7 +115,7 @@ for i in $(seq $((N+1)) 10); do
     sed -i "s|^Sheep .* \"sheep${i}\".*|# &|" "$DST"
 done
 
-active=$(grep -c '^Sheep' "$DST")
+active=$(grep -c '^Sheep' "$DST" || true)
 echo "------------------------------------------------------------"
 echo "World      : $DST"
 echo "Mode       : $MODE"