A Drupal 8 sub theme generator, with build tools.
Enables sub theme generation via drush 9.
Download the cog_tools module.
composer require drupal/cog_tools
Enable the cog_tools module
drush pm:enable cog_tools
Create a sub theme with drush.
drush generate cog
Answer the questions.
Enable your new sub theme. For a theme with the machine name durian:
drush theme:enable durian
Passing in arguments via the command line:
drush gen cog --answers '{"name":"Durian", "machine_name": "durian", "base_theme": "classy", "description": "What a nice theme.", "package": "Custom", "build_tasks": "yes", "layouts":"yes", "theme_settings":"yes","style_guide":"yes"}'
Any answers that are left off here will be asked still, so this could be handy if you have a few options you almost always select.