What is the aws command to verify my login credentials are correct? AKA whoami for aws-cli

TLDR

What is the aws-cli command to verify my login credentials are correct?
What is the whoami equivalent for the aws-cli?

Description of problem

I'm learning AWS technologies including serverless and using different accounts when working with different teams. I sometimes get errors that are due to using the wrong credentials or not having the permission to do something.

When I run into an error, the first thing I want to do is make sure I'm using the correct credentials, so I want a whoami command. So:

1. I want to know that my AWS credentials are valid,

2. What my AWS IAM login is. The equivalent of whoami in Windows or Unix. Obviously, if it just gives me who I am I know I'm valid!

3. What the rights are for the IAM user I'm logged in as. The IAM roles or permissions this IAM user has. See also Roles terms and concepts

What I've tried

So I've searched and found:

Verifying AWS Command Line Interface credentials are configured correctly - which again is similar. It has a link to named profiles which helps by giving me a command that should work aws ec2 describe-instances which works, and fills #1 from above list.

More searches give

• Why am I receiving errors when running AWS CLI commands?

Leads me to: Why am I receiving the error message "You are not authorized to perform this operation" when I try to launch an EC2 instance? - which I think could help me and answer this question but when I try the command:

aws --version
aws-cli/2.1.29 Python/3.8.8 Windows/10 exe/AMD64 prompt/off

aws sts decode-authorization-message --encoded-message encoded-message

An error occurred (InvalidAuthorizationMessageException) when calling the DecodeAuthorizationMessage operation: Message is not valid

Another link: Why can't I run AWS CLI commands on my EC2 instance?

which leads me back to a previous link...

I'm guessing that this is a simple request and has a simple answer. Please share it. Thanks.

aws sts get-caller-identity

{
    "UserId": "AIDAAA12345ABCDEFABCD",
    "Account": "123456789012",
    "Arn": "arn:aws:iam::123456789012:user/james"
}