Request and set temporary credentials in a shell environment.

install the assume-role script to somewhere in path.

Setup roles in ~/.aws/config and ~/.aws/credentials as documented in AWS CLI userguide

Example:

~/.aws/config

[profile management]
region=eu-central-1

[profile production]
role_arn=arn:aws:iam:123456:role/DeploymentRole
source_profile=management
mfa_serial=arn:aws:iam:633:mfa/jack   # optional
duration_seconds=3600                 # optional
external_id=abc123                    # optional

~/.aws/credentials

[management]
aws_access_key_id = ...
aws_secret_access_key = ...

Execute a script my-script using temporary IAM credentials for production

$ assume-role production /path/to/my-script

This will set AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY and AWS_SESSION_TOKEN for duration of the script execution.

without a command, assume-role will output the credentials:

$ assume-role production
export AWS_ACCESS_KEY_ID="...."
export AWS_SECRET_ACCESS_KEY="..."
export AWS_SESSION_TOKEN="..."

you can store the credentials for your shell session by doing

$ eval $(assume-role production)

This script aims to duplicate https://github.com/remind101/assume-role without support for windows PowerShell.