Baidu's https://blog.csdn.net/weixin_38003389/article/details/90696337
https://www.cnblogs.com/zgqbky/p/11699282.html Guoqiang (clear)
tar -xf mysql-5.7.26-1.el7.x86_64.rpm-bundle.tar
yum -y install mysql-comm*
systemctl start mysqld
systemctl enable mysqld
systemctl status mysqld
grep -i 'password' /var/log/mysqld.log
mysql -u root -p''
set global validate_password_policy=0;
set global validate_password_length=6;
alter user root@localhost identified by "123456";
mysql -uroot -p123456
show databases;
mysqldump -uroot -p123456 -A >all.sql
mysqldump -uroot -p123456 --all-databases >all2.sql
mysql -uroot -p123456 <all.sql