数据库mysql和mariadb初始安装后设置root密码可使用mysql_secure_installation工具：
# mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY!
In order to log into MariaDB to secure it, we'll need the current
password for the root user. If you've just installed MariaDB, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none):
OK, successfully used password, moving on...
Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.
Set root password? [Y/n] Y
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
... Success!
By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them. This is intended only for testing, and to make the installation
go a bit smoother. You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] Y
... Success!
Normally, root should only be allowed to connect from 'localhost'. This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] Y
... Success!
By default, MariaDB comes with a database named 'test' that anyone can
access. This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] Y
- Dropping test database...
... Success!
- Removing privileges on test database...
... Success!
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] Y
exit
... Success!
Cleaning up...
All done! If you've completed all of the above steps, your MariaDB
installation should now be secure.
Thanks for using MariaDB!
根据输入情况，自动化处理时可使用如下方式：
1、简单的一条命令，从互联网某大佬的文章中借鉴来的，但可能因我的环境不同提示些错误，但经尝试最终都可成功完成设置：
echo -e "\nY\n123456\n123456\nY\nn\nY\nY\n" | mysql_secure_installation
2、利用expect的shell脚本，以下保存文件后expect -f执行：
#!/usr/bin/expect
set timeout 10
spawn bash -c " mysql_secure_installation "
expect "Enter current password for root (enter for none): "
send "\n"
expect "Set root password? "
send "Y\n"
expect "New password:"
send "NPassword\n"
expect "Re-enter new password:"
send "NPassword\n"
expect "Remove anonymous users? "
send "Y\n"
expect "Disallow root login remotely? "
send "Y\n"
expect "Remove test database and access to it? "
send "Y\n"
expect "Reload privilege tables now? "
send "Y\n"
send "\n"
send "exit"
send "\n"
expect eof
3、其它expect类工具，如python，可实现但当前已满足需求未再尝试。
以上前两种方式都可以根据自己环境的情况去自定义配置参数是Y或N以及自定义密码，第三种实现后也同理。