all aws region codes

regions.txt

ap-south-1
eu-west-3
eu-north-1
eu-west-2
eu-west-1
ap-northeast-3
ap-northeast-2
ap-northeast-1
sa-east-1
ca-central-1
ap-southeast-1
ap-southeast-2
eu-central-1
us-east-1
us-east-2
us-west-1
us-west-2
cn-north-1
cn-northwest-1

$ for r in $(aws ec2 describe-regions --query 'Regions[*].RegionName' --output text); do echo $r; done >  aws_regions 
$ for r in $(aws --profile bjs ec2 describe-regions --query 'Regions[*].RegionName' --output text); do echo $r; done >>  aws_regions
$ cat aws_regions