my system is ubuntu:18.04. I download the course code from github and install the requiring tool.
sudo apt-get install build-essential g++ libx11-dev libxkbfile-dev libsecret-1-dev python-is-python3
then i input
yarn
there shows error
$ ./ci/dev/postinstall.sh
error: unknown option '-r'
error Command failed with exit code 1.
how can i fix it?