Presigned S3 download URL

Generate a time-limited download URL without making the object public

aws s3 presign s3://<name>/path/file.tgz --expires-in 3600

More aws commands

Update kubeconfig for EKS

aws eks update-kubeconfig --name <cluster> --region <id> --alias <cluster> --kubeconfig ~/.kube/config

Add/refresh an EKS context with a clean alias instead of the long ARN
ECR docker login

aws ecr get-login-password --region <id> | docker login --username AWS --password-stdin <id>.dkr.ecr.<id>.amazonaws.com

Auth Docker to ECR via stdin so the token never lands in shell history
SSM shell without SSH

aws ssm start-session --target i-<id> --region <id>

Open an interactive shell on an instance with no open port 22 or bastion
Tail Lambda/CloudWatch logs

aws logs tail /aws/lambda/<name> --follow --since 10m --format short

Live-stream a log group like tail -f. modern: replaces clunky filter-log-events polling
Simulate IAM policy decision

aws iam simulate-principal-policy --policy-source-arn <id> --action-names s3:GetObject --resource-arns <id> --query 'EvaluationResults[].{action:EvalActionName,decision:EvalDecision}' --output table

Test if a principal can do an action before granting; explains allow/deny