diff --git a/scripts/singularity_cmd b/scripts/singularity_cmd
index ff19e703..9246727c 100755
--- a/scripts/singularity_cmd
+++ b/scripts/singularity_cmd
@@ -31,8 +31,6 @@
 #  THE SOFTWARE.
 #
 
-set -eu
-
 function info() {
 	: #	echo -e "I: " "$@" >&2
 }
@@ -72,6 +70,13 @@ function readlink_f() {
 	readlink -f "$1" 2> /dev/null || python -c 'import sys, os ; print(os.path.realpath(sys.argv[1]))' "$1"
 }
 
+if [ "$#" = 0 ]; then
+	echo "Using as a library. Run with 'exec' or 'run' command and options."
+	exit 0
+fi
+
+set -eu
+
 info "PWD=$PWD"
 
 thisfile=$(readlink_f "$0")