**Example 1: To attach a policy to a thing group** The following ``attach-policy`` example attaches the specified policy to a thing group identified by its ARN. :: aws iot attach-policy \ --target "arn:aws:iot:us-west-2:123456789012:thinggroup/LightBulbs" \ --policy-name "UpdateDeviceCertPolicy" This command does not produce any output. For more information, see `Thing Groups <https://docs.aws.amazon.com/iot/latest/developerguide/thing-groups.html>`__ in the *AWS IoT Developers Guide*. **Example 2: To attach a policy to a certificate** The following ``attach-policy`` example attaches the policy ``UpdateDeviceCertPolicy`` to the principal specified by a certificate. :: aws iot attach-policy \ --policy-name UpdateDeviceCertPolicy \ --target "arn:aws:iot:us-west-2:123456789012:cert/4f0ba725787aa94d67d2fca420eca022242532e8b3c58e7465c7778b443fd65e" This command does not produce any output. For more information, see `Attach an AWS IoT Policy to a Device Certificate <https://docs.aws.amazon.com/iot/latest/developerguide/attach-policy-to-certificate.html>`__ in the *AWS IoT Developers Guide*.