docker exec <container-id> sh /test.sh

docker exec 7bd877d15c9b /bin/bash /test.sh

/test.sh

#!/bin/bash
echo "Hi"
echo
echo "This works fine"
sleep 5
echo "5"

ArgonQQ@Terminal ~  docker exec 7bd877d15c9b /bin/bash /test.sh
Hi

This works fine
5
ArgonQQ@Terminal ~