I am following the tutorial mentioned in this link -

The key was to put space between single quote ' and double quote " towards the end of your bash command.

Also, it is recommended to use the Data folder when it comes to mapping out your output file as stated in the GCP documentation:

gs://bucket-name/data /home/airflow/gcs/data: Stores the data that tasks produce and use. This folder is mounted on all worker nodes.