centos 安装mysql 登录进提示 Access denied for user 'root'@'localhost' (using password: NO)

# service mysqld  stop
# mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
# mysql -u root mysql
mysql> UPDATE user SET Password=PASSWORD('newpassword') where USER='root';
mysql> FLUSH PRIVILEGES;
mysql> quit

# service mysqld  restart
# mysql -uroot -p
Enter password: <输入新设的密码newpassword>