生成密码
执行 grub-mkpasswd-pbkdf2
user:~ $ grub-mkpasswd-pbkdf2
输入口令：
Reenter password:
PBKDF2 hash of your password is grub.pbkdf2.sha512.10000.1BB9B516B1658C99B71B3A4D4B1268A43A20C3C3AEAC7F558106DBC87118D5C34143005BBCBD5FF06D3158C9823596CD00568EEACB190E2A92D760EC049C9BCE.54A9AB1E031550AA919F67E427E33F2B8F14268FBCFFA4C2BFF51812D5F559142D8B313C63247D22EF3CA97FC4ED87A7B6FEB3764EAA17...
