The MySQL command-line tool. More information: https://www.mysql.com/.
mysql database_name
mysql -u user --password database_name
mysql -h database_host database_name
mysql --socket path/to/socket.sock
mysql -e "source filename.sql" database_name
mysqldump
(user will be prompted for a password):mysql --user user --password database_name < path/to/backup.sql
mysql --user user --password < path/to/backup.sql