~/.aws ~.aws/confg ~./aws/credentials IAM Access Key/Secret Key

 aws configure

aws configure --profile karan

aws s3 ls 

aws s3 ls profile --fubar

vi ~/.aws/config

vi ~/.aws/credentials

aws iam list-users --profile default

[ec2-user@ip-172-31-16-83 .aws]$ aws iam list-users

An error occurred (AccessDenied) when calling the ListUsers operation: User: arn:aws:sts::061116847625:assumed-role/S3FullAccessFromEC2NoCredReq/i-0622cebe406df06cd is not authorized to perform: iam:ListUsers on resource: arn:aws:iam::061116847625:user/