debian-sys-maint的密码是安装mysql时随时生成的
停止或重启服务都靠它
如果你修改了它的密码或覆盖掉密码，就会出现错误
error: ‘Access denied for user ‘debian-sys-maint’@’localhost’ (using password: YES)’
查看/etc/mysql/debian.cnf查看内容，可以看到有这个mysql连接用户：[client]
host = localhost
user = debian-sys-maint
password = G1I2JcALeXXvyC50
socket = /var/run/mysqld/mysqld.sock
[mysql_upgrade]
user = debian-sys-maint
password = G1I2JcALeXXvyC50
socket = /var/run/mysqld/mysqld.sock
basedir = /usr
直接用mysql登录，为debian-sys-maint用户改密：
mysql>SET PASSWORD FOR ‘debian-sys-maint’@’localhost’ = PASSWORD(‘这里就是上面看到的密码’);
mysql> flush privileges;
这样就OK了
如果删除了改用户，那只有添加了
mysql> GRANT ALL PRIVILEGES ON *.* TO ‘debian-sys-maint’@’localhost’ IDENTIFIED BY ‘这里就是上面看到的密码” WITH GRANT OPTION;
mysql> flush privileges;