gcloud alpha compute instances tail-serial-port-output

NAME: gcloud alpha compute instances tail-serial-port-output - periodically fetch new output from a virtual machine instance's serial port and display it as it becomes available
SYNOPSIS: gcloud alpha compute instances tail-serial-port-output INSTANCE_NAME [--port=PORT] [--zone=ZONE] [GCLOUD_WIDE_FLAG …]
DESCRIPTION: (ALPHA) gcloud alpha compute instances tail-serial-port-output is used to tail the output from a Compute Engine virtual machine instance's serial port. The serial port output from the instance will be printed to standard output. This information can be useful for diagnostic purposes.
EXAMPLES: To fetch new output from instance's serial port and display it, run:
gcloud alpha compute instances tail-serial-port-output example-instance --zone=us-central1-b
POSITIONAL ARGUMENTS: INSTANCE_NAME

Name of the instance to operate on. For details on valid instance names, refer to the criteria documented under the field 'name' at: https://cloud.google.com/compute/docs/reference/rest/v1/instances
FLAGS: --port=PORT

Instances can support up to four serial port outputs, numbered 1 through 4. By default, this command will return the output of the first serial port. Setting this flag will return the output of the requested serial port.

--zone=ZONE

Zone of the instance to operate on. If not specified, you might be prompted to select a zone (interactive mode only). gcloud attempts to identify the appropriate zone by searching for resources in your currently active project. If the zone cannot be determined, gcloud prompts you for a selection with all available Google Cloud Platform zones.
To avoid prompting when this flag is omitted, the user can set the compute/zone property:
gcloud config set compute/zone ZONE

A list of zones can be fetched by running:
gcloud compute zones list

To unset the property, run:
gcloud config unset compute/zone

Alternatively, the zone can be stored in the environment variable CLOUDSDK_COMPUTE_ZONE.
GCLOUD WIDE FLAGS: These flags are available to all commands: --access-token-file, --account, --billing-project, --configuration, --flags-file, --flatten, --format, --help, --impersonate-service-account, --log-http, --project, --quiet, --trace-token, --user-output-enabled, --verbosity.
Run $ gcloud help for details.
NOTES: This command is currently in alpha and might change without notice. If this command fails with API permission errors despite specifying the correct project, you might be trying to access an API with an invitation-only early access allowlist. These variants are also available:
gcloud compute instances tail-serial-port-output

gcloud beta compute instances tail-serial-port-output