mysql -u root
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

sudo mysqld_safe --skip-grant-tables
2017-05-19T11:54:35.6NZ mysqld_safe Logging to '/usr/local/var/mysql/mac.err'.
2017-05-19T11:54:35.6NZ mysqld_safe Starting mysqld daemon with databases from /usr/local/var/mysql
2017-05-19T11:54:35.6NZ mysqld_safe mysqld from pid file /usr/local/var/mysql/mac.pid ended

mysql.server start --skip-grant-tables

mysql -u root -p
mysql> use mysql;
mysql> update user set password=PASSWORD("newpass") where User='ENTER-USER-NAME-HERE';

mysqladmin -u root -p oldpassword newpass