知耻后勇
1,sudo vi /etc/default/grub; default config as below:
# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'
GRUB_DEFAULT="1 > 6"
#属性名：默认启动项（就是我要的开机默认启动系统）
#值说明：
# 数字：从0开始（按照开机选择界面的顺序对应）
# saved:默认上次的启动项
#使用 '>' 符号来指定有一个子菜单（注意符号 > 和数字 3 之间有空格，所以需要双引号）。
在这种情况下，我在主菜单中选择第2个选项（索引1），在子菜单中选择第四个选项（索引3）。
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true ->隐藏菜单
#属性名：是否显示等待倒计时
#值说明：true：不显示，false：显示
GRUB_TIMEOUT=10 ->设置进入默认启动项的等候时间，默认值10秒，按自己需要修改
#属性名：进入默认启动项的等候时间
#值说明：单位：秒，默认10秒，-1表示一直等待
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
#属性名：内核启动参数的默认值
#值说明：quiet splash为不显示启动信息，安静的启动，如值为空则显示启动信息
GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0"
#属性名：手动添加内核启动参数
#值说明：默认为空，可以添加你需要的参数，以 “name=value” 的格式添加，多个参数用空格隔开
#例如：GRUB_CMDLINE_LINUX="name1=value1 name2=value2"
# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"
# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console
# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480
# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true
# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"
# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"
#属性名：图形界面分辨率
#值说明：分辨率啦（还要怎么说明），修改时记得去掉前面的“#”
2,after modify /etc/default/grub run sudo update-grub
then file /boot/grub/grub.cfg will be updated，but donot modify /boot/grub/grub.cfg directly，
if you want to modify /etc/default/grub，please run sudo update-grub
3,介绍ubuntu 16.04 切换内核的方法：
(1)首先找到内核名称,通过一下命令：grep menuentry /boot/grub/grub.cfg
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
menuentry_id_option=""
export menuentry_id_option
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-fc70dee1-e972-415e-ad84-ba286999600b' {
submenu 'Ubuntu 高级选项' $menuentry_id_option 'gnulinux-advanced-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu，Linux 4.15.0-112-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-112-generic-advanced-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-112-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-112-generic-init-upstart-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-112-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-112-generic-recovery-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu，Linux 4.15.0-99-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-99-generic-advanced-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-99-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-99-generic-init-upstart-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-99-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-99-generic-recovery-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu，Linux 4.15.0-55-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-55-generic-advanced-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-55-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-55-generic-init-upstart-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-55-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-55-generic-recovery-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu，Linux 4.154.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-29-generic-advanced-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-29-generic (upstart)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-29-generic-init-upstart-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'Ubuntu, with Linux 4.15.0-29-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-29-generic-recovery-fc70dee1-e972-415e-ad84-ba286999600b' {
menuentry 'System setup' $menuentry_id_option 'uefi-firmware' {
(2)从当前配置看出，GRUB_DEFAULT="1 > 6"，当前的启动时内核是Ubuntu：Ubuntu，Linux 4.15.0-55-generic
(3)uname -a
Ubuntu，Linux 4.15.0-55-generic
(4)如果要切换到：Ubuntu，Linux 4.15.0-29-generic
(5)修改GRUB_DEFAULT="1 > 6"---〉as GRUB_DEFAULT="1 > 9" ;/etc/default/grub;保存
(6)然后执行sudo update-grub
然后重启sudo reboot
(7) uname -a
Ubuntu，Linux 4.15.0-29-generic
成功切换