1. 查看磁盘占用情况
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/nvme0n1p5 181M 141M 27M 85% /boot
/dev/nvme0n1p8 71G 26G 41G 39% /home
/dev/nvme0n1p1 96M 48M 49M 50% /boot/efi
tmpfs 1.6G 16K 1.6G 1% /run/user/121
tmpfs 1.6G 44K 1.6G 1% /run/user/1000
发现/boot确实占用率很高。
2. uname -a (查看当前使用的内核版本)
lenmom@M1701:~$ uname -a Linux M1701 4.15.0-43-generic #46-Ubuntu SMP Thu Dec 6 14:45:28 UTC 2018 x86_64
3.查看已安装的内核版本
lenmom@M1701:~$ dpkg --get-selections |grep linux binutils-x86-64-linux-gnu install console-setup-linux install libselinux1:amd64 install linux-base install linux-firmware install linux-generic install linux-headers-4.15.0-39 install linux-headers-4.15.0-39-generic install linux-headers-4.15.0-43 install linux-headers-4.15.0-43-generic install linux-headers-generic install linux-image-4.15.0-29-generic deinstall linux-image-4.15.0-39-generic install linux-image-4.15.0-43-generic install linux-image-generic install linux-libc-dev:amd64 install linux-modules-4.15.0-29-generic deinstall linux-modules-4.15.0-39-generic install linux-modules-4.15.0-43-generic install linux-modules-extra-4.15.0-29-generic deinstall linux-modules-extra-4.15.0-39-generic install linux-modules-extra-4.15.0-43-generic install linux-signed-generic install linux-sound-base install pptp-linux install syslinux install syslinux-common install syslinux-legacy install util-linux install
能看到已经安装的版本，其中带image的一般就是旧版本，其中
a）deinstall代表是已经删除的旧版本
b) install是还没有删除的旧版本内核
4. 删除多余的内核文件
通过uname -a可以查看到当前正在使用的内核版本，把不是当前版本的处于install状态的image-xxx-generic文件卸载掉，对于本例中linux-modules-extra-4.15.0-39-generic是多余的内核文件，正在使用的是linux-modules-extra-4.15.0-43-generic，开始卸载。
卸载命令为sudo apt-get remove linux-modules-xxx-generic，其中xxx为要卸载的内核版本号
lenmom@M1701:~$ sudo apt-get remove linux-modules-4.15.0-39-generic Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED: linux-image-4.15.0-39-generic linux-modules-4.15.0-39-generic 0 upgraded, 0 newly installed, 2 to remove and 105 not upgraded. 1 not fully installed or removed. After this operation, 74.6 MB disk space will be freed. Do you want to continue? [Y/n] y (Reading database ... 187447 files and directories currently installed.) Removing linux-image-4.15.0-39-generic (4.15.0-39.42) ... I: /vmlinuz.old is now a symlink to boot/vmlinuz-4.15.0-43-generic I: /initrd.img.old is now a symlink to boot/initrd.img-4.15.0-43-generic /etc/kernel/postrm.d/initramfs-tools: update-initramfs: Deleting /boot/initrd.img-4.15.0-39-generic /etc/kernel/postrm.d/zz-update-grub: Generating grub configuration file ... Found linux image: /boot/vmlinuz-4.15.0-43-generic Found initrd image: /boot/initrd.img-4.15.0-43-generic Found Windows Boot Manager on /dev/nvme0n1p1@/EFI/Microsoft/Boot/bootmgfw.efi Adding boot menu entry for EFI firmware configuration done Removing linux-modules-4.15.0-39-generic (4.15.0-39.42) ... Setting up initramfs-tools (0.130ubuntu3.5) ... update-initramfs: deferring update (trigger activated) Processing triggers for initramfs-tools (0.130ubuntu3.5) ... update-initramfs: Generating /boot/initrd.img-4.15.0-43-generic W: APT had planned for dpkg to do more than it reported back (6 vs 10). Affected packages: initramfs-tools:amd64
5. 使用du -h再次查看/boot空间
lenmom@M1701:~$ df -h Filesystem Size Used Avail Use% Mounted on /dev/nvme0n1p5 181M 75M 94M 45% /boot /dev/nvme0n1p8 71G 26G 41G 39% /home /dev/nvme0n1p1 96M 48M 49M 50% /boot/efi tmpfs 1.6G 16K 1.6G 1% /run/user/121 tmpfs 1.6G 44K 1.6G 1% /run/user/1000
我们发现，/boot空间的确已经释放出来了。