--query
で絞って--output text
を指定する。
queryの絞り込みはこの記事が参考になる。
https://qiita.com/draco/items/fa09ae0c2f51de9de449
$ aws ec2 describe-instances --query 'Reservations[*].Instances[*].PublicDnsName' --output text
ec2-xxx-xxx-xxx-xxx.ap-northeast-1.compute.amazonaws.com
ec2-xxx-xxx-xxx-xxx.ap-northeast-1.compute.amazonaws.com
ec2-xxx-xxx-xxx-xxx.ap-northeast-1.compute.amazonaws.com
ec2-xxx-xxx-xxx-xxx.ap-northeast-1.compute.amazonaws.com
...