How to clean up /boot?

[Ralf Mardorf]

On Wed, 11 Jan 2017 09:05:54 +0100, Sascha Manns wrote:
>Hi,
>
>On 08.01.2017 17:18, Peng Yu wrote:
>> It doesn't work.  
>Maybe this one works for you.
>1.) create a new textfile in a editor and place it in ~/home (eg vim
>~/remove-old-kernels.sh)
>2.) Fill it with that:
>#!/bin/bash
>dpkg -l 'linux-[ihs]*' | sed '/^ii/!d;/'"$(uname -r | sed
>"s/\([-0-9]*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^
>]*\).*/\1/;/[0-9]/!d' | tee to_removed
>cat to_be_removed | xargs sudo apt-get -y purge
>rm to_be_removed
>
>It deletes all kernels in /boot and holds the last one.

Hi,

_warning_ this script is dangerous!

Firs of all, regarding to the typo and the fact that a novice unlikely
will be able to fix the line wrapping issues, the script does nothing
at all. However, if you fix the script, get rid of the wrapped lines
and edit "tee to_removed" to "tee to_be_removed" the script could
automatically purge all kernels and render the install unbootable.
For demonstration I replaced "-y" by "--dry-run", then I didn't boot
Ubuntu, but run it in a container, so when "uname -r" does show the
running kernel, it's a kernel that is not a kernel installed by Ubuntu,
ergo what ever sed should do (I didn't check if it's correct, but
assuming it should be), "uname -r" not necessarily does keeps the
latest kernel. If it should keep a kernel, than the kernel that is
running. Even if you don't run Ubuntu in a container, it might not keep
the latest kernel. Such a script at least should first show what it
will do and than require interaction, so at least the "-y" option
should be removed.

[root at archlinux rocketmouse]# systemd-nspawn -qD /mnt/moonstudio 
[root at moonstudio ~]# lsb_release -d
Description:	Ubuntu 16.04.1 LTS
[root at moonstudio ~]# ls -hl /boot/vmlinuz-*
-rw------- 1 root root 6.8M Jan  7 03:36 /boot/vmlinuz-4.4.0-59-lowlatency
lrwxrwxrwx 1 root root   27 Jan 10 17:44 /boot/vmlinuz-lowlatency -> vmlinuz-4.4.0-59-lowlatency
[root at moonstudio ~]# uname -r
4.8.13-1-ARCH
[root at moonstudio ~]# cd /home/weremouse/Desktop/
[root at moonstudio Desktop]# cat crappy_script.sh 
#!/bin/bash

dpkg -l 'linux-[ihs]*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\([-0-9]*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' | tee to_be_removed

cat to_be_removed | xargs sudo apt-get --dry-run purge

exit
[root at moonstudio Desktop]# ./crappy_script.sh 
linux-headers-4.4.0-59
linux-headers-4.4.0-59-lowlatency
linux-image-4.4.0-59-lowlatency
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  linux-headers-4.4.0-59* linux-headers-4.4.0-59-lowlatency* linux-headers-lowlatency*
  linux-image-4.4.0-59-lowlatency* linux-image-lowlatency* linux-lowlatency*
0 upgraded, 0 newly installed, 6 to remove and 0 not upgraded.
Purg linux-lowlatency [4.4.0.59.62]
Purg linux-headers-lowlatency [4.4.0.59.62]
Purg linux-headers-4.4.0-59-lowlatency [4.4.0-59.80]
Purg linux-headers-4.4.0-59 [4.4.0-59.80]
Purg linux-image-lowlatency [4.4.0.59.62]
Purg linux-image-4.4.0-59-lowlatency [4.4.0-59.80]
[root at moonstudio Desktop]#

Btw. does the script remove modules build manually with dkms, too?

Regards,
Ralf