Good news, since version 3.1.6 Really Simple SSL supports WP-CLI for basic SSL management. The Really Simple SSL commands can be accessed with wp rsssl. The plugin currently supports three basic commands: one to activate SSL (activate_ssl), one to deactivate SSL (deactivate_ssl), and one to update a Really Simple SSL option.
php wp rsssl activate_ssl
php wp rsssl deactivate_ssl
php wp rsssl update_option --site_has_ssl=true
php wp rsssl update_option --dismiss_all_notices=true --x_xss_protection=one
Or, depending on your wp cli setup, php wp-cli.phar instead of php wp.
We would like to extend the plugins WP-CLI functionality with your suggestions. Please us know what functionality you would like to have included in the Really Simple SSL WP-CLI commands!