$ ec2-describe-instances-go -r ap-northeast-1 | jq .

$ go get github.com/ryotarai/ec2-describe-instances-go

$ for i in `seq 0 3`; do time aws ec2 describe-instances >/dev/null; done
aws ec2 describe-instances > /dev/null  2.15s user 0.11s system 21% cpu 10.548 total
aws ec2 describe-instances > /dev/null  2.17s user 0.11s system 25% cpu 9.009 total
aws ec2 describe-instances > /dev/null  2.14s user 0.11s system 20% cpu 10.771 total
aws ec2 describe-instances > /dev/null  2.15s user 0.11s system 25% cpu 8.899 total

$ for i in `seq 0 4`; do time ec2-describe-instances-go -r ap-northeast-1 >/dev/null; done
ec2-describe-instances-go -r ap-northeast-1 > /dev/null  0.54s user 0.02s system 23% cpu 2.405 total
ec2-describe-instances-go -r ap-northeast-1 > /dev/null  0.55s user 0.02s system 32% cpu 1.707 total
ec2-describe-instances-go -r ap-northeast-1 > /dev/null  0.55s user 0.02s system 31% cpu 1.766 total
ec2-describe-instances-go -r ap-northeast-1 > /dev/null  0.55s user 0.02s system 31% cpu 1.769 total
ec2-describe-instances-go -r ap-northeast-1 > /dev/null  0.55s user 0.02s system 30% cpu 1.860 total