In the newest version of MySQL or later one, it has not need to install the startup item “MySQL_StartupItem.pkg”, also use the default password as “root any more. After installed, Pop-up prompts a temporary password, as the message says:
2016-03-08T15:35:58.686693Z 1 [Note] A temporary password is generated for root@localhost: E%*oVnN?d7sx
In terminal, type in “sudo vi /etc/bashrc”，then configure mysql and mysqladmin path in bash.
or in user’s path, touch ~/.bash_profile
mysqladmin -u root -p password
mysql -u root -p