digest=$(curl -s --head "https://gcr.io/v2/tensorflow-sigs/build/manifests/$2" | egrep -o "sha256:[[:alnum:]]*")
          # Find the line matching the regex "sigbuild-r2.9" (with quotes) and
          # replace just the digest portion in it
          sed -i"" "/\"$1\"/ s/sha256:[[:alnum:]]*/$digest/g" tensorflow/tools/toolchains/remote_config/configs.bzl
          echo "success."
        }