The -p option is not needed by the default installation of mariadb-server on CentOS Linux release 7.3.1611 (Core)
Including it without knowing to press enter for no password results in an authentication error:
root@netmon ~# mysql -u root -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
Alternatively, it could be noted to leave the password field blank when asked.
