1、修改grub本机环境：ubuntu18.0.4
添加GRUB_HIDDEN_TIMEOUT=10
可以发现重启后无法进入grub,修改后在倒计时按Shift或Esc键即可进入grub
$ sudo vim /etc/default/grub2、更新grub并重启
$ sudo update-grub $ sudo reboot二、设置全局Grub密码
1、生成密码
$ sudo grub-mkpasswd-pbkdf2 ###密码设置为123456 Enter password: Reenter password: PBKDF2 hash of your password is grub.pbkdf2.sha512.10000.2484786B75AC1034FCD1F839B8EBEF355365B87C543932B0BF0C9E89D24DA6568249851BAAC5C746AB250812FBEDE084590DDD643A9EF482EC9A6FCB1B66EBAD.A54EDA92F12FB534D494A9235ACDC1085D910EED1C3F97AC60A0EA782E086FBD321DAE5DD3712BA7FFD672A47D58CD4954235C13A212F579750BF6FA7FE240A72、修改00_header
添加至末尾即可
password wielun 123456:明文方式
$ sudo vim /etc/grub.d/00_header cat << EOF set superusers="wielun" # password wielun 123456 password_pbkdf2 wielun grub.pbkdf2.sha512.10000.2484786B75AC1034FCD1F839B8EBEF355365B87C543932B0BF0C9E89D24DA6568249851BAAC5C746AB250812FBEDE084590DDD643A9EF482EC9A6FCB1B66EBAD.A54EDA92F12FB534D494A9235ACDC1085D910EED1C3F97AC60A0EA782E086FBD321DAE5DD3712BA7FFD672A47D58CD4954235C13A212F579750BF6FA7FE240A7 EOF
$ sudo update-grub3、重启查看结果
可以选择这2个选项都需要输入密码
1、修改10_linux上面的会导致重启机器就需要输入密码，很麻烦
保留上面修改，添加--unrestricted
$ sudo vim /etc/grub.d/10_linux
$ sudo update-grub2、重启查看结果
可以发现可以正常重启，进入第二项则需要输入密码
参考文章：How to Add Password Protect to Grub Boot Menu in Linux Mint, Ubuntu, Debian
