smmm@smmm-linux:/var/www/html$ composer create-project laravel/laravel test
Cannot create cache directory /home/smmm/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/smmm/.composer/cache/files/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/smmm/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache
Согласно Вашему пути т.е. это следует /home/smmm/.composer/cache/repo/https---packagist.org
, необходимо попробовать эти команды для решения проблемы.