Magento ≥ 2.2
bin/magento config:set dev/js/merge_files 0
bin/magento cache:clean
Magento < 2.2
mysql --host=<host> --user=<user> --password=<password> -D <database> -e "\
UPDATE core_config_data SET value = 0 WHERE 'dev/js/merge_files' = path; \
";
bin/magento cache:clean