aws sts assume-role --role-arn arn:aws:iam::123456789012:role/role-name --role-session-name "RoleSession1" --profile IAM-user-name > assume-role-output.txt
Using the AWS CLI, you can call an AWS STS API like AssumeRole or GetFederationToken and then capture the resulting output. The following example shows a call to AssumeRole that sends the output to a file. In the example, the profile parameter is assumed to be a profile in the AWS CLI configuration file. It is also assumed to reference credentials for an IAM user who has permissions to assume the role.
Linux
$ export AWS_ACCESS_KEY_ID=ASIAIOSFODNN7EXAMPLE
$ export AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
$ export AWS_SESSION_TOKEN=AQoDYXdzEJr...<remainder of session token>
$ aws ec2 describe-instances --region us-west-1
Windows
C:\> SET AWS_ACCESS_KEY_ID=ASIAIOSFODNN7EXAMPLE
C:\> SET AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
C:\> SET AWS_SESSION_TOKEN=AQoDYXdzEJr...<remainder of token>
C:\> aws ec2 describe-instances --region us-west-1