Keeping your kernel up to date on Gentoo can be a bit daunting, especially when you are running the “keyworded” kernel, meaning not the stable version, but the “always latest” version by keyword ~amd64. There’s a new version almost every week and updating it manually can be quite annoying over time. At least it felt for me …
make
make modules
make modules_install
make install
Then after that, updating the grub config … And what was the command to update the kernel-dependent modules again? Oh ya …
emerge @module-rebuild
For some reason, I can never remember that one … Don’t ask me why.
So, I came up with a little helper in form of a bash script that does pretty much all the work for me, all I have to do is tell it which kernel version I want to have and it does all the magic for me. All I need to do from time to time is clean up old kernel installations.
#!/bin/bash
selected_kernel=""
kernel_base_directory="/usr/src/"
kernel_directory=""
usage() {
printf "Usage: $0 -k=[<selected_kernel>]\n"
printf "Usage: $0 --kernel=[<selected_kernel>]\n"
printf "Usage: $0 --latest\n\n"
printf "<selected_kernel> is the full kernel version string.\n"
printf "If the '--latest' (without the quotation marks) option is used, the latest available kernel version will be compiled.\n\n"
printf "Available kernel versions (current active version is marked with an asterisk):\n`eselect kernel list`\n" 1>&2;
exit 1;
}
for i in "$@"; do
case $i in
-k=*|--kernel=*)
selected_kernel="${i#*=}"
shift
;;
--latest)
selected_kernel=$(eselect kernel list | tail -1 | awk '{print $2}' | sed 's/[][]//g')
;;
-*|--*)
echo "Unknown option $i"
exit 1
;;
*)
usage
;;
esac
done
# if no kernel is selected, show help text
if [ -z "${selected_kernel}" ] ; then
usage
fi
#set the new kernel directory
kernel_directory="${kernel_base_directory}${selected_kernel}"
# compiling new kernel
compile_new_kernel() {
echo "New Kernel Version: ${selected_kernel}"
echo "Entering kernel directory: ${kernel_directory}";
cd ${kernel_directory}
echo "Copying kernel configuration";
cp /usr/src/linux/.config .
echo "Switching symlink to new kernel";
eselect kernel set ${selected_kernel}
echo "Applying config via 'make olddefconfig'";
make olddefconfig
echo "Building new kernel";
make -j12
echo "Building modules";
make modules
echo "Installing modules";
make modules_install
echo "Installing new kernel";
make install
echo "Configuring grub2";
cp /boot/grub/grub.cfg /boot/grub/grub.cfg.bak
GRUB_USE_LINUX_LABEL=true grub-mkconfig -o /boot/grub/grub.cfg
echo "Re-compile kernel dependant modules";
emerge -av @module-rebuild
echo "Kernel update complete. You may restart your computer now."
echo "Feel free to run 'eclean-kernel -n 2' to cleanup old kernel files but keep the latest 2."
}
if [ -d ${kernel_directory} ] ; then
current_kernel_version=$(uname -r)
if [ ${selected_kernel} == "linux-${current_kernel_version}" ] ; then
echo "You are currently running this kernel version."
echo "Exiting!";
exit;
else
compile_new_kernel
fi
else
echo "Error: Directory ${kernel_directory} does not exist."
echo "Exiting!";
exit;
fi
Save this as e.g. /usr/bin/kernel-update, make sure it is executable via chmod +x /usr/bin/kernel-update and all you have to do to switch to your desired kernel version is (Example: latest installed kernel):
kernel-update --latest
If you want a specific version, first check which versions are available via eselect kernel list and take the version string for a kernel as the argument. For example to build linux-5.17.7-gentoo:
kernel-update -k=linux-5.17.7-gentoo
If you like this script, let me know. I am always open to improvements, so feel free to suggest them!