参考：https://www.cnblogs.com/lxg0/articles/5598205.html
1、进到数据库进行操作
[root@localhost etc]# mysql
Welcome to the MariaDB monitor. Commands end with ; or g.
Your MariaDB connection id is 7
Server version: 5.5.41-MariaDB MariaDB Server
Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
MariaDB [(none)]> mysql
-> ;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds
to your MariaDB server version for the right syntax to use near 'mysql' at line 1MariaDB [(none)]> update user set password=password("123456")where user='root';
ERROR 1046 (3D000): No database selected
2、选择数据库
MariaDB [(none)]> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
3、用户root添加密码
MariaDB [mysql]> update user set password=password("123456")where user='root';
Query OK, 0 rows affected (0.00 sec)
Rows matched: 4 Changed: 0 Warnings: 0
4、赋予权限
MariaDB [mysql]> flush privileges;
Query OK, 0 rows affected (0.00 sec)
5、退出，重新登录
MariaDB [mysql]> exit
Bye
6、尝试无密码是否可以登录
[root@localhost etc]# mysql
提示错误
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
7、输入密码登陆
[root@localhost etc]# mysql -u root -p123456
Welcome to the MariaDB monitor. Commands end with ; or g.
Your MariaDB connection id is 9
Server version: 5.5.41-MariaDB MariaDB Server
Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
MariaDB [(none)]>
其他写法会报错：
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'mysqladmin -u root -p password root' at line 1
二、允许远程访问
参考：https://www.cnblogs.com/latteyan/articles/5831132.html
GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'%' IDENTIFIED BY 'mypassword' WITH GRANT OPTION;
如果你想允许用户myuser从ip为192.168.1.3的主机连接到mysql服务器，并使用mypassword作为密码
GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'192.168.1.3' IDENTIFIED BY 'mypassword' WITH GRANT OPTION;
三、启动mariadb
systemctl start mariadb ==> 启动mariadb
systemctl enable mariadb ==> 开机自启动
https://blog.csdn.net/fordarkuse5/article/details/51111281