ubuntu 内核升级降级

# 正在用的内核版本
uname --r

# 查看都安装了什么内核
dpkg --get-selections |grep linux
    console-setup-linux                    install
    libselinux1:amd64                    install
    linux-base                            install
    linux-firmware                        install
    linux-generic                        install
    linux-headers-4.4.0-186                install
    linux-headers-4.4.0-186-generic        install
    linux-headers-generic                install
    linux-image-4.4.0-186-generic        install
    linux-image-generic                    install
    linux-libc-dev:amd64                install
    linux-modules-4.4.0-186-generic        install
    linux-modules-extra-4.4.0-186-generic        install
    util-linux                    install            install

# dpkg -l |grep linux（ii 用remove删除 rl用apt-get purge name删除）
root@u1604-164-111:~# dpkg -l |grep linux
    ii  console-setup-linux                   1.108ubuntu15.5   
    ii  libselinux1:amd64                     2.4-3build2       
    ii  linux-base                            4.5ubuntu1.2~16.04
    ii  linux-firmware                        1.157.23          
    ii  linux-generic                         4.4.0.186.192     
    ii  linux-headers-4.4.0-186               4.4.0-186.216     
    ii  linux-headers-4.4.0-186-generic       4.4.0-186.216     
    ii  linux-headers-generic                 4.4.0.186.192     
    ii  linux-image-4.4.0-186-generic         4.4.0-186.216     
    ii  linux-image-generic                   4.4.0.186.192     
    ii  linux-libc-dev:amd64                  4.4.0-210.242     
    ii  linux-modules-4.4.0-186-generic       4.4.0-186.216     
    ii  linux-modules-extra-4.4.0-186-generic 4.4.0-186.216     
    ii  util-linux                            2.27.1-6ubuntu3.10
# 删除不用的内核（正在使用的不能删除）（ii 用remove删除 rl用apt-get purge name删除）
apt remove linux-image-generic
apt purge  linux-image-X.X.X-XXX-generic

# 查看使用了
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-edb86ff9-de0a-47a8-8048-86c3ac974228' {
submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-edb86ff9-de0a-47a8-8048-86c3ac974228' {
    menuentry 'Ubuntu, with Linux 4.4.0-186-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-186-generic-advanced-edb86ff9-de0a-47a8-8048-86c3ac974228' {
    menuentry 'Ubuntu, with Linux 4.4.0-186-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.4.0-186-generic-recovery-edb86ff9-de0a-47a8-8048-86c3ac974228' {

# 配置默认启动
vim /etc/default/grub
###默认指向你想要启动的内核###
GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux linux-image-4.15.0-72-generic"

# 重启服务器
reboot