# service mysqld stop
# mysqld_safe --user=root --skip-grant-tables &
# mysql mysql
mysql> UPDATE user SET Password=password('新しいパスワード') WHERE Host='localhost' and User='root';
# mysqld_safe --user=root --skip-grant-tables &
# mysql mysql
mysql> UPDATE user SET Password=password('新しいパスワード') WHERE Host='localhost' and User='root';