This assumes you have already configured the aws command line tool. If not, check out my article on Getting Started with the AWS CLI.

The aws iam list-instance-profiles command can be used to list the Instance Profiles you have created. Something like this should be returned.

~]$ aws iam list-instance-profiles
{
    "InstanceProfiles": [
        {
            "Path": "/",
            "InstanceProfileName": "my-instance-profile",
            "InstanceProfileId": "AIPA2MITL76GNDM4CZFIM",
            "Arn": "arn:aws:iam::123456789012:instance-profile/my-instance-profile",
            "CreateDate": "2024-01-26T02:20:03+00:00",
             "Roles": [
                {
                    "Path": "/",
                    "RoleName": "test",
                    "RoleId": "AROA2MITL76GF46NSCA6E",
                    "Arn": "arn:aws:iam::123456789012:role/my-role",
                    "CreateDate": "2024-01-26T02:13:17+00:00",
                    "AssumeRolePolicyDocument": {
                        "Version": "2012-10-17",
                        "Statement": [
                            {
                                "Effect": "Allow",
                                "Principal": {
                                    "AWS": "arn:aws:iam::123456789012:user/johndoe"
                                },
                                "Action": "sts:AssumeRole",
                                "Condition": {}
                            }
                        ]
                    }
                }
            ]
        }
    ]
}

The  aws ec2 associate-iam-instance-profile command can be used to associate the instance profile with your EC2 instances.

~]$ aws ec2 associate-iam-instance-profile --instance-id i-abc123def456gh789 --iam-instance-profile Name=my-instance-profile
{
    "IamInstanceProfileAssociation": {
        "AssociationId": "iip-assoc-04a03786337a32660",
        "InstanceId": "i-abc123def456gh789",
        "IamInstanceProfile": {
            "Arn": "arn:aws:iam::123456789012:instance-profile/my-instance-profile",
            "Id": "AIPA2MITL76GNDM4CZFIM"
        },
        "State": "associated"
    }
}