User:Pietinger/New at Gentoo

I wrote this article so that I can link to it in the Gentoo forums if users have questions about it.

Initial Installation

The most important thing you need to know about Gentoo before you try to install it:

Take your time !

Installing Gentoo will take longer than installing a binary Linux distribution ... and you will also need more time for reading manuals, because your normal Linux knowledge is not (yet) sufficient. Plan several days.

Before you jump into Handbook:AMD64 to install Gentoo, I would like to recommend a few things:

First, read this fabulous article by our famous wiki editor @maffblaster (in my opinion, it should actually be the first page in our Handbook):

User:Maffblaster/Drafts/Gentoo_Primers/The_Gentoo_Primer

and right after that these articles:

Benefits_of_Gentoo

Installation

Secondly, even if you want to use a manually configured kernel, you should first install the precompiled kernel image sys-kernel/gentoo-kernel-bin because you can then select it at any time via the boot manager and thus have a backup kernel when your manually configured kernel causes problems. This is the first option in Handbook:AMD64/Installation/Kernel.

If you have never configured a kernel manually, I recommend you read this first - including all the linked articles: User:Pietinger/Tutorials/Manual_kernel_configuration

Now you should have a better basis for deciding whether you want to go down this path.

If you are unsure which option to choose here: Handbook:AMD64/Installation/Bootloader then I would recommend:

For an OpenRC system use grub - for a systemd system use systemd-boot.

Don't worry if you want to boot your kernel directly via UEFI, you can always install "Alternative 2: EFI Stub" later. Just read User:Pietinger/Tutorials/Boot_kernel_via_UEFI after you have completed all installation steps.

However, a boot manager to start with is very handy in case you have a problem with a new / your manually configured kernel.

It might be helpful to have the following quick guide printed out next to you while reading the Handbook:AMD64 and to compare it (and to copy the commands from there if you are unsure somewhere): User:Pietinger/Draft/Quick_Installation_OpenRC_for_an_UEFI_System

Pause during Installation

Thirdly, you can take a break at any time during the initial installation to continue the next day. If you are at any step after this one:

Handbook:AMD64/Installation/Base#Preparing_for_a_bootloader

and before you have completed this step:

Handbook:AMD64/Installation/Bootloader#Rebooting_the_system

you can pause by executing both in reverse order:

Instead of a reboot, you naturally perform a

root #shutdown -h now

and if you want start the next day you boot again: Handbook:AMD64/Installation/Media#Booting_the_installation_media

and do these steps again = Chrooting into your Gentoo system:

1. Handbook:AMD64/Installation/Disks#Mounting_the_root_partition =>

root #mount /dev/sda3 /mnt/gentoo

2. Handbook:AMD64/Installation/Base#Mounting_the_necessary_filesystems =>

root #arch-chroot /mnt/gentoo

3. Handbook:AMD64/Installation/Base#Entering_the_new_environment =>

root #source /etc/profile

4. Mount your boot partition OR your ESP, depending if you use old BIOS boot or UEFI boot - Handbook:AMD64/Installation/Base#Preparing_for_a_bootloader =>

root #mount /dev/sda1 /efi

Now continue where you left off yesterday ;-)

These steps are also necessary to switch back to your installation when your system does not boot after Handbook:AMD64/Installation/Bootloader#Rebooting_the_system.

The most common mistake beginners make with Gentoo

Now that you are done with the basic installation, you should keep your Gentoo up to date.

The best way to keep your Gentoo up to date is to update everything after an emerge --sync with an emerge -uUDv @world.

Gentoo also allows you to update only individual packages and not everything at once. For example, you are allowed to update only the kernel. You have two options for this:

root #emerge -uD gentoo-kernel-bin

or

root #emerge -1uD gentoo-kernel-bin

You may have noticed that I also use this parameter -1 in my CheatSheet for a kernel update. What does this do?

As you have probably already seen from the installation, there are packages that require other packages - dependencies. Gentoo - Portage - knows these dependencies and automatically resolves them for you and installs these packages automatically. For example, if KDE needs a “gcc”, you don't have to install it beforehand, but it is automatically installed during the installation of KDE (in reality, every program needs the gcc, so it is/was already in stage3). Now take a look at the file /var/lib/portage/world. Do you see the “gcc” in your world file? No. This file only contains all the packages that you have just explicitly installed, but not the dependencies. There is a good reason for this:

If you no longer want a package and therefore uninstall it, it will disappear from the world file. If you then do an emerge -c, all packages that were ONLY a dependency of this package will also be uninstalled ...

... as long as you have not “included” these dependencies in the world file. However, this is exactly what happens if you update individual packages and do not use this parameter -1. Without the -1 parameter for a single update, such packages are added to the world file ... and THEN they are no longer deleted with an emerge -c. This means: You should actually always use the -1 parameter for every SINGLE update - you only don't need it for an update to @world. (Actually, this only applies to slotted packages - but as a Gentoo newbie you won't know what that is yet).

Only omit this parameter if you really want to keep a specific version. In this example you can see that I wanted to keep a specific kernel and therefore portage automatically made this additional entry in my /var/lib/portage/world:

FILE /var/lib/portage/world

...
sys-kernel/gentoo-sources
sys-kernel/gentoo-sources:6.12.21
...

With today's update to @world I got a new kernel version. Of course I want to delete the old version, but portage will not delete the protected version 6.12.21 (and of course the current one), only the old one:

root #emerge -cp

[...]

>>> These are the packages that would be unmerged:

 sys-kernel/gentoo-sources
    selected: 6.14.2 
   protected: none 
     omitted: 6.12.21 6.14.3 

[...]

You should now know all about this parameter so that you understand what this thread is about: [[1]]

Further note: It is strongly recommended not to edit file /var/lib/portage/world manually. If you want to uninstall a package, let Portage do it for you. Why? Because Portage may find out that it is a bad idea. Try an emerge -c gcc. Portage will not allow you to do it. If you add the -v parameter, Portage will also tell you why it's a bad idea:

root #emerge -cv gcc

Calculating dependencies... done!
  sys-devel/gcc-14.2.1_p20241221 pulled in by:
    @system requires sys-devel/gcc
...
    sys-libs/glibc-2.40-r8 requires >=sys-devel/gcc-6.2

>>> No packages selected for removal by depclean

Deleting a GCC version would only be possible if you have a new (additional) version after an update to @world. Then Portage would allow you to delete the old version. If you just want to check if you could uninstall a package use the parameter -p to be on the safe side; i.e. emerge -cpv PACKAGENAME.