如何彻底移除Ubuntu 16.04系统中的旧内核？

Hey there, I’ve run into this exact headache a bunch of times with Ubuntu 16.04—those stubborn old kernels hanging around in /boot even after autoremove fails can be super frustrating. Let’s walk through a thorough fix to free up that disk space properly:

Step 1: Lock Down Your Active Kernel #

First rule of kernel cleanup: never delete the one you’re currently running. Let’s confirm which kernel that is:

uname -r

Jot down that version (it’ll look like 4.4.0-190-generic)—we’ll keep this one plus any recent backup kernels you want to hold onto.

Step 2: Identify All Installed Kernel Packages #

Next, list every kernel-related package on your system to see what’s lingering:

dpkg --list | grep linux-image
dpkg --list | grep linux-headers

Look for packages with version numbers lower than your active kernel (and outside your backup set)—these are our targets for removal.

Step 3: Fix Autoremove’s "Blind Spot" #

Sometimes autoremove ignores old kernels because they were marked as manually installed. Fix this by marking them as automatic, so apt knows they’re safe to clean up:

sudo apt-mark auto linux-image-<OLD-VERSION>-generic linux-headers-<OLD-VERSION>-generic

Replace <OLD-VERSION> with the actual old kernel number (e.g., 4.4.0-189). Repeat this for every old kernel package pair you want to get rid of.

Step 4: Fully Purge Old Kernels #

Use purge instead of regular remove to delete the packages and their leftover config files—this is way more thorough:

sudo apt-get purge linux-headers-<OLD-VERSION>-generic linux-image-<OLD-VERSION>-generic

Run this command for each old kernel pair you identified earlier.

Step 5: Clean Up Stray /boot Files #

If you still see old kernel files in /boot (like vmlinuz-<OLD-VERSION> or initrd.img-<OLD-VERSION>), double-check their corresponding packages were purged first. Then delete the stray files manually:

sudo rm /boot/vmlinuz-<OLD-VERSION>-generic /boot/initrd.img-<OLD-VERSION>-generic /boot/config-<OLD-VERSION>-generic /boot/System.map-<OLD-VERSION>-generic

Be extra careful here—don’t touch any files matching your active kernel version!

Step 6: Update GRUB #

Finish up by updating your GRUB config to remove references to the deleted kernels:

sudo update-grub

That should wipe out all those leftover kernel files and free up that missing 500MB+ of space in /boot.

内容的提问来源于stack exchange，提问作者user788957