好久沒碰過更換root密碼的這爛事了，今天重溫了一遍。。。
一般上，伺服器一旦運行了，最好的情況是永遠無需碰它的設置。但有時候真的無可避免。這回，在使用了往常用的修復手法后，卻被系統直接KO，被系統提醒我 “請仔細詳讀用戶手冊中，Security這欄目。。。”
找了來看，一頭霧水。最後去問神了，結果還是一直被KO。直到最後在Stack Overflow的這篇文章内，才找到真正的答案。。。
是的，系統升級了，往常用的mysqld_safe已經不存在了。現在更方便的衹需設置好伺服器的運作環境常量，重啓即可。長話短說，流程轉載在下方：
1. Stop mysql:
> systemctl stop mysqld
2. Set the mySQL environment option
> systemctl set-environment MYSQLD_OPTS=”–skip-grant-tables”
3. Start mysql usig the options you just set
> systemctl start mysqld
4. Login as root
> mysql -u root
5. Update the root user password with these mysql commands:
mysql> UPDATE mysql.user SET authentication_string = PASSWORD(‘MyNewPassword’) -> WHERE User = ‘root’ AND Host = ‘localhost’;
mysql> FLUSH PRIVILEGES;
mysql> quit
(for 5.7.6 and later, you should use mysql> ALTER USER ‘root’@’localhost’ IDENTIFIED BY ‘MyNewPass’;)
6. Stop mysql
> systemctl stop mysqld
7. Unset the mySQL envitroment option so it starts normally next time
> systemctl unset-environment MYSQLD_OPTS
8. Start mysql normally:
> systemctl start mysqld
9. Try to login using your new password:
> mysql -u root -p