diff --git a/script_setup.sh b/script_setup.sh
index 648a3588e37c0f668a8fbe2e90ee5a0bb6e82193..54e31cdc40b865599397d5bc6ff73352747ac5d8 100755
--- a/script_setup.sh
+++ b/script_setup.sh
@@ -20,7 +20,7 @@ if grep -i centos /etc/redhat-release &>/dev/null; then
 
 	# Extend python path for externals (mailinglogger)
 	EXTERNAL_PYTHON_DIR="/sw/atlas/tdaq/$TDAQ_RELEASE/installed/external/$CMTCONFIG/lib/python3.7/site-packages/"
-	if ! ls $EXTERNAL_PYTHON_DIR; then
+	if ! ls $EXTERNAL_PYTHON_DIR &>/dev/null; then
 		echo "error: cannot find external python packages in $EXTERNAL_PYTHON_DIR"
 		return 1
 	fi