I tried doing setcors / getcors to a single file, but I get
CommandException: URI gs://bucket/cat.png must name a bucket for the setcors command
gsutil getcors gs://bucket.commondatastorage.googleapis.com/cat.png
CommandException: "getcors" command must specify a bucket
It (setcors / getcors) works for the entire bucket, but the documentation says differently.
Do I need to update my gsutil utility ?
No, it can only be specified at the bucket level. Do you have a URL for the spot in the docs that says you can set it on individual objects?