Ubuntu 修改默认启动内核（kernel）

Ubuntu 设定启动kernel

1. 查看都有那些内核

cat /boot/grub/grub.cfg | grep menuentry

2. 查看 /boot/grub/grub.cfg 中的内容

menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-0d5ce63b-8900-4a2b-ac84-251bf287bfbf' {
submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-0d5ce63b-8900-4a2b-ac84-251bf287bfbf' {
menuentry 'Ubuntu, with Linux 5.11.0-41-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.11.0-41-generic-advanced-0d5ce63b-8900-4a2b-ac84-251bf287bfbf' {
menuentry 'Ubuntu, with Linux 5.11.0-41-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.11.0-41-generic-recovery-0d5ce63b-8900-4a2b-ac84-251bf287bfbf' {
menuentry 'Ubuntu, with Linux 5.11.0-40-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.11.0-40-generic-advanced-0d5ce63b-8900-4a2b-ac84-251bf287bfbf' {
menuentry 'Ubuntu, with Linux 5.11.0-40-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnul　

menuentry(主菜单）：是系统每次启动默认的kernel，对应 /etc/default/grub 中 GRUB_DEFAULT=0

submenu(子菜单）：包含系统中所有的启动kernel。

3. 我们想以submenu中 Linux 5.11.0-40-generic 启动，只需要把 /etc/default/grub 中 GRUB_DEFAULT="1 >2"，注意1和>之间有空格。

vim /etc/default/grub

文件内容：

# 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 >2"
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

# 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"　

4. 更新grub.cfg

update-grub

5. 重启生效

 Ubuntu 添加kernel启动参数

1. 在下面的文件中 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" 中添加参数

sudo vim /etc/default/grub

2. 使参数生效

sudo update-grub

3. 重启

4. 查看启动项是否正确

cat /proc/cmdline