📝 Made more notes on gentoo and updating

gentoo/updating.md

@@ -1,17 +1,174 @@
 # Updating Gentoo
 
+Gentoo has a lot of little nuances that are worth noting.
+
+## Basic Updating
+
+Not too much to go into depth on here.
+
 ```sh
+emerge --sync
 emaint -a sync
 ```
 
-```sh
-emerge -avuDN @world
-```
-
-```sh
-dispatch-conf
-```
-
 ```sh
 eselect news read all | less
 ```
+
+```sh
+emerge -auDN @world
+```
+
+```sh
+emerge -a --depclean
+```
+
+## Unmasking
+
+Sometimes you'll have to unmask packages that are considered unstable (usually
+by tacking on the `amd64` flag). Consult
+/etc/portage/package.accept_keywords/package.unmask file for formatting.
+
+## Use Flags
+
+Adjusting program flags are one of the major features of Gentoo. To unmask
+packages, just dump it into /etc/portage/package.use/package.use file.
+
+If during installation of a new package you get a warning to add necessary use
+flags, you can do so by manually editing aforementioned package.use file or
+using:
+
+```sh
+dispatch-conf
+```
+
+## Updating Kernels
+
+This is a bit more involved. Firstly you'll need sys-kernel/gentoo-sources. If
+you need a specific version, you'll usually first have to unmask it by version
+number (see unmasking above).
+
+Once installed navigate to `/usr/src/linux-version-you-want-to-use`.
+
+Inside that linux version, you'll need to compile the kernel. I've opted to use
+modprobed-db for this purpose as it creates a minimal config by simply
+periodically running a cron job to see what modules/flags need to be set in the
+kernel. This file lives in `~/.config/modprobed.db`.
+
+To use this as your default navigate into the kernel folder in `/usr/src` and
+run:
+
+```sh
+make LSMOD=$HOME/.config/modprobed.db localmodconfig
+```
+
+This will generate the `.config` file necessary. You might still need to adjust
+certain flags if you find the kernel doesn't work or doesn't have the features
+you want. In that case run:
+
+```sh
+make menuconfig
+```
+
+And adjust the config options that are missing/misconfigured.
+
+If all seems to be to your liking however, just make the kernel:
+
+```sh
+make -j$(nproc)
+```
+
+Or specify the amount of jobs you want make to run at a time, I like 6.
+
+After compiling (could take a while depending). Install the modules:
+
+```sh
+make modules_install
+```
+
+And also install the kernel:
+
+```sh
+make install
+```
+
+## NVIDIA Drivers
+
+The NVIDIA drivers have to be reinstalled for every kernel you install, in order
+to do this, you'll first need to either `eselect` your new kernel or manually
+symlink the new kernel yourself. The reasons you might want to manually symlink
+it is if you manually changed the name of your kernel in the `.config` file.
+
+To use the `eselect version`, simply run:
+
+```sh
+eselect kernel list
+```
+
+And choose the new kernel:
+
+```sh
+eselect kernel set 2
+```
+
+Or whichever number your kernel is. If you instead wish to manually update the
+symbolic link, you can do so by invoking:
+
+```sh
+ln -sf /usr/src/linux-kernel-you-want-to-use /usr/src/linux
+```
+
+Either way, this will select your kernel and now you can install the NVIDIA
+modules you need:
+
+```sh
+emerge -a @module-rebuild
+```
+
+Once this is done, go ahead and reboot. If all went well, you'll have a new
+kernel installed and ready to go!
+
+## Uninstalling Old/Unwanted Kernels
+
+Okay, so there is a package for this called `eclean`, but I'd prefer to take a
+hands on approach to this as removing kernels should be done with care. Removing
+your last working kernel is NOT something you ever want to do (and why you
+should always backup /boot along with almost everything on your system).
+
+Navigate to `/boot`. There you will find files like:
+
+```
+config-6.12.54-gentoo-dist
+initramfs-6.12.54-gentoo-dist.img
+System.map-6.12.54-gentoo-dist
+vmlinuz-6.12.54-gentoo-dist
+```
+
+And if you ever recompiled the same kernel, it will also generate `.old` files.
+
+```
+config-6.12.54-gentoo-dist.old
+initramfs-6.12.54-gentoo-dist.img.old
+System.map-6.12.54-gentoo-dist.old
+vmlinuz-6.12.54-gentoo-dist.old
+```
+
+Once you have confirmed these are your old/unwanted kernels, remove them
+carefully using rm, make sure not to use the wildcard `*` character here as you
+can easily accidentally remove something you want here.
+
+```
+rm config-6.12.54-gentoo-dist
+rm initramfs-6.12.54-gentoo-dist.img
+rm System.map-6.12.54-gentoo-dist
+rm vmlinuz-6.12.54-gentoo-dist
+```
+
+And make sure to regenerate your grub config so that it's made "aware" of the
+changes.
+
+```sh
+grub-mkconfig -o /boot/grub/grub.cfg
+```
+
+And that's it!