How to use mysql_plugin utility?

I tried to follow this official documentation to install unix_socket plugin using mysql_plugin utility but getting an error that > Cannot read plugin config file unix_socket. Bad format in plugin > configuration file. FROM alpine:edge RUN set -ex \ && apk add mariadb mariadb-client \ && mysql_install_db --user=mysql --skip-name-resolve \ && echo 'auth_socket' >> /usr/lib/mariadb/plugin/unix_socket.ini \ && mysql_plugin --basedir=/usr --datadir=/var/lib/mysql --plugin_dir=/usr/lib/mariadb/plugin unix_socket ENABLE CMD ["mysqld"] I cross checked the ini file. cat /usr/lib/mariadb/plugin/unix_socket.ini auth_socket