check docker hub rate limit balance

docker-hub-rate-limit.sh

# annonymous
TOKEN=$(curl "https://auth.docker.io/token?service=registry.docker.io&scope=repository:ratelimitpreview/test:pull" \
  | jq -r .token) && curl --head -H "Authorization: Bearer $TOKEN" https://registry-1.docker.io/v2/ratelimitpreview/test/manifests/latest \
  | grep 'RateLimit'

# authenticated
# note that there should be no output
# https://docs.docker.com/docker-hub/download-rate-limit/#i-dont-see-any-ratelimit-headers
TOKEN=$(curl --user 'username:password' "https://auth.docker.io/token?service=registry.docker.io&scope=repository:ratelimitpreview/test:pull" | jq -r .token) \
  && curl --head -H "Authorization: Bearer $TOKEN" https://registry-1.docker.io/v2/ratelimitpreview/test/manifests/latest \
  | grep 'RateLimit'