<chapter xmlns="http://docbook.org/ns/docbook"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude" xml:id="sec-installation">
  <title>Installing NixOS</title>
  <section xml:id="sec-installation-booting">
    <title>Booting from the install medium</title>
    <para>
      To begin the installation, you have to boot your computer from the
      install drive.
    </para>
    <orderedlist numeration="arabic">
      <listitem>
        <para>
          Plug in the install drive. Then turn on or restart your
          computer.
        </para>
      </listitem>
      <listitem>
        <para>
          Open the boot menu by pressing the appropriate key, which is
          usually shown on the display on early boot. Select the USB
          flash drive (the option usually contains the word
          <quote>USB</quote>). If you choose the incorrect drive, your
          computer will likely continue to boot as normal. In that case
          restart your computer and pick a different drive.
        </para>
        <note>
          <para>
            The key to open the boot menu is different across computer
            brands and even models. It can be <keycap>F12</keycap>, but
            also <keycap>F1</keycap>, <keycap>F9</keycap>,
            <keycap>F10</keycap>, <keycap>Enter</keycap>,
            <keycap>Del</keycap>, <keycap>Esc</keycap> or another
            function key. If you are unsure and don’t see it on the
            early boot screen, you can search online for your computers
            brand, model followed by <quote>boot from usb</quote>. The
            computer might not even have that feature, so you have to go
            into the BIOS/UEFI settings to change the boot order. Again,
            search online for details about your specific computer
            model.
          </para>
          <para>
            For Apple computers with Intel processors press and hold the
            <keycap>⌥</keycap> (Option or Alt) key until you see the
            boot menu. On Apple silicon press and hold the power button.
          </para>
        </note>
        <note>
          <para>
            If your computer supports both BIOS and UEFI boot, choose
            the UEFI option.
          </para>
        </note>
        <note>
          <para>
            If you use a CD for the installation, the computer will
            probably boot from it automatically. If not, choose the
            option containing the word <quote>CD</quote> from the boot
            menu.
          </para>
        </note>
      </listitem>
      <listitem>
        <para>
          Shortly after selecting the appropriate boot drive, you should
          be presented with a menu with different installer options.
          Leave the default and wait (or press <keycap>Enter</keycap> to
          speed up).
        </para>
      </listitem>
      <listitem>
        <para>
          The graphical images will start their corresponding desktop
          environment and the graphical installer, which can take some
          time. The minimal images will boot to a command line. You have
          to follow the instructions in
          <xref linkend="sec-installation-manual" /> there.
        </para>
      </listitem>
    </orderedlist>
  </section>
  <section xml:id="sec-installation-graphical">
    <title>Graphical Installation</title>
    <para>
      The graphical installer is recommended for desktop users and will
      guide you through the installation.
    </para>
    <orderedlist numeration="arabic">
      <listitem>
        <para>
          In the <quote>Welcome</quote> screen, you can select the
          language of the Installer and the installed system.
        </para>
        <tip>
          <para>
            Leaving the language as <quote>American English</quote> will
            make it easier to search for error messages in a search
            engine or to report an issue.
          </para>
        </tip>
      </listitem>
      <listitem>
        <para>
          Next you should choose your location to have the timezone set
          correctly. You can actually click on the map!
        </para>
        <note>
          <para>
            The installer will use an online service to guess your
            location based on your public IP address.
          </para>
        </note>
      </listitem>
      <listitem>
        <para>
          Then you can select the keyboard layout. The default keyboard
          model should work well with most desktop keyboards. If you
          have a special keyboard or notebook, your model might be in
          the list. Select the language you are most comfortable typing
          in.
        </para>
      </listitem>
      <listitem>
        <para>
          On the <quote>Users</quote> screen, you have to type in your
          display name, login name and password. You can also enable an
          option to automatically login to the desktop.
        </para>
      </listitem>
      <listitem>
        <para>
          Then you have the option to choose a desktop environment. If
          you want to create a custom setup with a window manager, you
          can select <quote>No desktop</quote>.
        </para>
        <tip>
          <para>
            If you don’t have a favorite desktop and don’t know which
            one to choose, you can stick to either GNOME or Plasma. They
            have a quite different design, so you should choose
            whichever you like better. They are both popular choices and
            well tested on NixOS.
          </para>
        </tip>
      </listitem>
      <listitem>
        <para>
          You have the option to allow unfree software in the next
          screen.
        </para>
      </listitem>
      <listitem>
        <para>
          The easiest option in the <quote>Partitioning</quote> screen
          is <quote>Erase disk</quote>, which will delete all data from
          the selected disk and install the system on it. Also select
          <quote>Swap (with Hibernation)</quote> in the dropdown below
          it. You have the option to encrypt the whole disk with LUKS.
        </para>
        <note>
          <para>
            At the top left you see if the Installer was booted with
            BIOS or UEFI. If you know your system supports UEFI and it
            shows <quote>BIOS</quote>, reboot with the correct option.
          </para>
        </note>
        <warning>
          <para>
            Make sure you have selected the correct disk at the top and
            that no valuable data is still on the disk! It will be
            deleted when formatting the disk.
          </para>
        </warning>
      </listitem>
      <listitem>
        <para>
          Check the choices you made in the <quote>Summary</quote> and
          click <quote>Install</quote>.
        </para>
        <note>
          <para>
            The installation takes about 15 minutes. The time varies
            based on the selected desktop environment, internet
            connection speed and disk write speed.
          </para>
        </note>
      </listitem>
      <listitem>
        <para>
          When the install is complete, remove the USB flash drive and
          reboot into your new system!
        </para>
      </listitem>
    </orderedlist>
  </section>
  <section xml:id="sec-installation-manual">
    <title>Manual Installation</title>
    <para>
      NixOS can be installed on BIOS or UEFI systems. The procedure for
      a UEFI installation is broadly the same as for a BIOS
      installation. The differences are mentioned in the following
      steps.
    </para>
    <para>
      The NixOS manual is available by running
      <literal>nixos-help</literal> in the command line or from the
      application menu in the desktop environment.
    </para>
    <para>
      To have access to the command line on the graphical images, open
      Terminal (GNOME) or Konsole (Plasma) from the application menu.
    </para>
    <para>
      You are logged-in automatically as <literal>nixos</literal>. The
      <literal>nixos</literal> user account has an empty password so you
      can use <literal>sudo</literal> without a password:
    </para>
    <programlisting>
$ sudo -i
</programlisting>
    <para>
      You can use <literal>loadkeys</literal> to switch to your
      preferred keyboard layout. (We even provide neo2 via
      <literal>loadkeys de neo</literal>!)
    </para>
    <para>
      If the text is too small to be legible, try
      <literal>setfont ter-v32n</literal> to increase the font size.
    </para>
    <para>
      To install over a serial port connect with
      <literal>115200n8</literal> (e.g.
      <literal>picocom -b 115200 /dev/ttyUSB0</literal>). When the
      bootloader lists boot entries, select the serial console boot
      entry.
    </para>
    <section xml:id="sec-installation-manual-networking">
      <title>Networking in the installer</title>
      <para>
        <anchor xml:id="sec-installation-booting-networking" />
        <!-- legacy anchor -->
      </para>
      <para>
        The boot process should have brought up networking (check
        <literal>ip a</literal>). Networking is necessary for the
        installer, since it will download lots of stuff (such as source
        tarballs or Nixpkgs channel binaries). It’s best if you have a
        DHCP server on your network. Otherwise configure networking
        manually using <literal>ifconfig</literal>.
      </para>
      <para>
        On the graphical installer, you can configure the network, wifi
        included, through NetworkManager. Using the
        <literal>nmtui</literal> program, you can do so even in a
        non-graphical session. If you prefer to configure the network
        manually, disable NetworkManager with
        <literal>systemctl stop NetworkManager</literal>.
      </para>
      <para>
        On the minimal installer, NetworkManager is not available, so
        configuration must be perfomed manually. To configure the wifi,
        first start wpa_supplicant with
        <literal>sudo systemctl start wpa_supplicant</literal>, then run
        <literal>wpa_cli</literal>. For most home networks, you need to
        type in the following commands:
      </para>
      <programlisting>
&gt; add_network
0
&gt; set_network 0 ssid &quot;myhomenetwork&quot;
OK
&gt; set_network 0 psk &quot;mypassword&quot;
OK
&gt; set_network 0 key_mgmt WPA-PSK
OK
&gt; enable_network 0
OK
</programlisting>
      <para>
        For enterprise networks, for example
        <emphasis>eduroam</emphasis>, instead do:
      </para>
      <programlisting>
&gt; add_network
0
&gt; set_network 0 ssid &quot;eduroam&quot;
OK
&gt; set_network 0 identity &quot;myname@example.com&quot;
OK
&gt; set_network 0 password &quot;mypassword&quot;
OK
&gt; set_network 0 key_mgmt WPA-EAP
OK
&gt; enable_network 0
OK
</programlisting>
      <para>
        When successfully connected, you should see a line such as this
        one
      </para>
      <programlisting>
&lt;3&gt;CTRL-EVENT-CONNECTED - Connection to 32:85:ab:ef:24:5c completed [id=0 id_str=]
</programlisting>
      <para>
        you can now leave <literal>wpa_cli</literal> by typing
        <literal>quit</literal>.
      </para>
      <para>
        If you would like to continue the installation from a different
        machine you can use activated SSH daemon. You need to copy your
        ssh key to either
        <literal>/home/nixos/.ssh/authorized_keys</literal> or
        <literal>/root/.ssh/authorized_keys</literal> (Tip: For
        installers with a modifiable filesystem such as the sd-card
        installer image a key can be manually placed by mounting the
        image on a different machine). Alternatively you must set a
        password for either <literal>root</literal> or
        <literal>nixos</literal> with <literal>passwd</literal> to be
        able to login.
      </para>
    </section>
    <section xml:id="sec-installation-manual-partitioning">
      <title>Partitioning and formatting</title>
      <para>
        <anchor xml:id="sec-installation-partitioning" />
        <!-- legacy anchor -->
      </para>
      <para>
        The NixOS installer doesn’t do any partitioning or formatting,
        so you need to do that yourself.
      </para>
      <para>
        The NixOS installer ships with multiple partitioning tools. The
        examples below use <literal>parted</literal>, but also provides
        <literal>fdisk</literal>, <literal>gdisk</literal>,
        <literal>cfdisk</literal>, and <literal>cgdisk</literal>.
      </para>
      <para>
        The recommended partition scheme differs depending if the
        computer uses <emphasis>Legacy Boot</emphasis> or
        <emphasis>UEFI</emphasis>.
      </para>
      <section xml:id="sec-installation-manual-partitioning-UEFI">
        <title>UEFI (GPT)</title>
        <para>
          <anchor xml:id="sec-installation-partitioning-UEFI" />
          <!-- legacy anchor -->
        </para>
        <para>
          Here's an example partition scheme for UEFI, using
          <literal>/dev/sda</literal> as the device.
        </para>
        <note>
          <para>
            You can safely ignore <literal>parted</literal>'s
            informational message about needing to update /etc/fstab.
          </para>
        </note>
        <orderedlist numeration="arabic">
          <listitem>
            <para>
              Create a <emphasis>GPT</emphasis> partition table.
            </para>
            <programlisting>
# parted /dev/sda -- mklabel gpt
</programlisting>
          </listitem>
          <listitem>
            <para>
              Add the <emphasis>root</emphasis> partition. This will
              fill the disk except for the end part, where the swap will
              live, and the space left in front (512MiB) which will be
              used by the boot partition.
            </para>
            <programlisting>
# parted /dev/sda -- mkpart primary 512MB -8GB
</programlisting>
          </listitem>
          <listitem>
            <para>
              Next, add a <emphasis>swap</emphasis> partition. The size
              required will vary according to needs, here a 8GB one is
              created.
            </para>
            <programlisting>
# parted /dev/sda -- mkpart primary linux-swap -8GB 100%
</programlisting>
            <note>
              <para>
                The swap partition size rules are no different than for
                other Linux distributions.
              </para>
            </note>
          </listitem>
          <listitem>
            <para>
              Finally, the <emphasis>boot</emphasis> partition. NixOS by
              default uses the ESP (EFI system partition) as its
              <emphasis>/boot</emphasis> partition. It uses the
              initially reserved 512MiB at the start of the disk.
            </para>
            <programlisting>
# parted /dev/sda -- mkpart ESP fat32 1MB 512MB
# parted /dev/sda -- set 3 esp on
</programlisting>
          </listitem>
        </orderedlist>
        <para>
          Once complete, you can follow with
          <xref linkend="sec-installation-manual-partitioning-formatting" />.
        </para>
      </section>
      <section xml:id="sec-installation-manual-partitioning-MBR">
        <title>Legacy Boot (MBR)</title>
        <para>
          <anchor xml:id="sec-installation-partitioning-MBR" />
          <!-- legacy anchor -->
        </para>
        <para>
          Here's an example partition scheme for Legacy Boot, using
          <literal>/dev/sda</literal> as the device.
        </para>
        <note>
          <para>
            You can safely ignore <literal>parted</literal>'s
            informational message about needing to update /etc/fstab.
          </para>
        </note>
        <orderedlist numeration="arabic">
          <listitem>
            <para>
              Create a <emphasis>MBR</emphasis> partition table.
            </para>
            <programlisting>
# parted /dev/sda -- mklabel msdos
</programlisting>
          </listitem>
          <listitem>
            <para>
              Add the <emphasis>root</emphasis> partition. This will
              fill the the disk except for the end part, where the swap
              will live.
            </para>
            <programlisting>
# parted /dev/sda -- mkpart primary 1MB -8GB
</programlisting>
          </listitem>
          <listitem>
            <para>
              Finally, add a <emphasis>swap</emphasis> partition. The
              size required will vary according to needs, here a 8GiB
              one is created.
            </para>
            <programlisting>
# parted /dev/sda -- mkpart primary linux-swap -8GB 100%
</programlisting>
            <note>
              <para>
                The swap partition size rules are no different than for
                other Linux distributions.
              </para>
            </note>
          </listitem>
        </orderedlist>
        <para>
          Once complete, you can follow with
          <xref linkend="sec-installation-manual-partitioning-formatting" />.
        </para>
      </section>
      <section xml:id="sec-installation-manual-partitioning-formatting">
        <title>Formatting</title>
        <para>
          <anchor xml:id="sec-installation-partitioning-formatting" />
          <!-- legacy anchor -->
        </para>
        <para>
          Use the following commands:
        </para>
        <itemizedlist>
          <listitem>
            <para>
              For initialising Ext4 partitions:
              <literal>mkfs.ext4</literal>. It is recommended that you
              assign a unique symbolic label to the file system using
              the option <literal>-L label</literal>, since this makes
              the file system configuration independent from device
              changes. For example:
            </para>
            <programlisting>
# mkfs.ext4 -L nixos /dev/sda1
</programlisting>
          </listitem>
          <listitem>
            <para>
              For creating swap partitions: <literal>mkswap</literal>.
              Again it’s recommended to assign a label to the swap
              partition: <literal>-L label</literal>. For example:
            </para>
            <programlisting>
# mkswap -L swap /dev/sda2
</programlisting>
          </listitem>
          <listitem>
            <para>
              <emphasis role="strong">UEFI systems</emphasis>
            </para>
            <para>
              For creating boot partitions: <literal>mkfs.fat</literal>.
              Again it’s recommended to assign a label to the boot
              partition: <literal>-n label</literal>. For example:
            </para>
            <programlisting>
# mkfs.fat -F 32 -n boot /dev/sda3
</programlisting>
          </listitem>
          <listitem>
            <para>
              For creating LVM volumes, the LVM commands, e.g.,
              <literal>pvcreate</literal>, <literal>vgcreate</literal>,
              and <literal>lvcreate</literal>.
            </para>
          </listitem>
          <listitem>
            <para>
              For creating software RAID devices, use
              <literal>mdadm</literal>.
            </para>
          </listitem>
        </itemizedlist>
      </section>
    </section>
    <section xml:id="sec-installation-manual-installing">
      <title>Installing</title>
      <para>
        <anchor xml:id="sec-installation-installing" />
        <!-- legacy anchor -->
      </para>
      <orderedlist numeration="arabic">
        <listitem>
          <para>
            Mount the target file system on which NixOS should be
            installed on <literal>/mnt</literal>, e.g.
          </para>
          <programlisting>
# mount /dev/disk/by-label/nixos /mnt
</programlisting>
        </listitem>
        <listitem>
          <para>
            <emphasis role="strong">UEFI systems</emphasis>
          </para>
          <para>
            Mount the boot file system on <literal>/mnt/boot</literal>,
            e.g.
          </para>
          <programlisting>
# mkdir -p /mnt/boot
# mount /dev/disk/by-label/boot /mnt/boot
</programlisting>
        </listitem>
        <listitem>
          <para>
            If your machine has a limited amount of memory, you may want
            to activate swap devices now
            (<literal>swapon device</literal>). The installer (or
            rather, the build actions that it may spawn) may need quite
            a bit of RAM, depending on your configuration.
          </para>
          <programlisting>
# swapon /dev/sda2
</programlisting>
        </listitem>
        <listitem>
          <para>
            You now need to create a file
            <literal>/mnt/etc/nixos/configuration.nix</literal> that
            specifies the intended configuration of the system. This is
            because NixOS has a <emphasis>declarative</emphasis>
            configuration model: you create or edit a description of the
            desired configuration of your system, and then NixOS takes
            care of making it happen. The syntax of the NixOS
            configuration file is described in
            <xref linkend="sec-configuration-syntax" />, while a list of
            available configuration options appears in
            <xref linkend="ch-options" />. A minimal example is shown in
            <link linkend="ex-config">Example: NixOS
            Configuration</link>.
          </para>
          <para>
            The command <literal>nixos-generate-config</literal> can
            generate an initial configuration file for you:
          </para>
          <programlisting>
# nixos-generate-config --root /mnt
</programlisting>
          <para>
            You should then edit
            <literal>/mnt/etc/nixos/configuration.nix</literal> to suit
            your needs:
          </para>
          <programlisting>
# nano /mnt/etc/nixos/configuration.nix
</programlisting>
          <para>
            If you’re using the graphical ISO image, other editors may
            be available (such as <literal>vim</literal>). If you have
            network access, you can also install other editors – for
            instance, you can install Emacs by running
            <literal>nix-env -f '&lt;nixpkgs&gt;' -iA emacs</literal>.
          </para>
          <variablelist>
            <varlistentry>
              <term>
                BIOS systems
              </term>
              <listitem>
                <para>
                  You <emphasis>must</emphasis> set the option
                  <xref linkend="opt-boot.loader.grub.device" /> to
                  specify on which disk the GRUB boot loader is to be
                  installed. Without it, NixOS cannot boot.
                </para>
                <para>
                  If there are other operating systems running on the
                  machine before installing NixOS, the
                  <xref linkend="opt-boot.loader.grub.useOSProber" />
                  option can be set to <literal>true</literal> to
                  automatically add them to the grub menu.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                UEFI systems
              </term>
              <listitem>
                <para>
                  You <emphasis>must</emphasis> set the option
                  <xref linkend="opt-boot.loader.systemd-boot.enable" />
                  to <literal>true</literal>.
                  <literal>nixos-generate-config</literal> should do
                  this automatically for new configurations when booted
                  in UEFI mode.
                </para>
                <para>
                  You may want to look at the options starting with
                  <link linkend="opt-boot.loader.efi.canTouchEfiVariables"><literal>boot.loader.efi</literal></link>
                  and
                  <link linkend="opt-boot.loader.systemd-boot.enable"><literal>boot.loader.systemd-boot</literal></link>
                  as well.
                </para>
              </listitem>
            </varlistentry>
          </variablelist>
          <para>
            If you need to configure networking for your machine the
            configuration options are described in
            <xref linkend="sec-networking" />. In particular, while wifi
            is supported on the installation image, it is not enabled by
            default in the configuration generated by
            <literal>nixos-generate-config</literal>.
          </para>
          <para>
            Another critical option is <literal>fileSystems</literal>,
            specifying the file systems that need to be mounted by
            NixOS. However, you typically don’t need to set it yourself,
            because <literal>nixos-generate-config</literal> sets it
            automatically in
            <literal>/mnt/etc/nixos/hardware-configuration.nix</literal>
            from your currently mounted file systems. (The configuration
            file <literal>hardware-configuration.nix</literal> is
            included from <literal>configuration.nix</literal> and will
            be overwritten by future invocations of
            <literal>nixos-generate-config</literal>; thus, you
            generally should not modify it.) Additionally, you may want
            to look at
            <link xlink:href="https://github.com/NixOS/nixos-hardware">Hardware
            configuration for known-hardware</link> at this point or
            after installation.
          </para>
          <note>
            <para>
              Depending on your hardware configuration or type of file
              system, you may need to set the option
              <literal>boot.initrd.kernelModules</literal> to include
              the kernel modules that are necessary for mounting the
              root file system, otherwise the installed system will not
              be able to boot. (If this happens, boot from the
              installation media again, mount the target file system on
              <literal>/mnt</literal>, fix
              <literal>/mnt/etc/nixos/configuration.nix</literal> and
              rerun <literal>nixos-install</literal>.) In most cases,
              <literal>nixos-generate-config</literal> will figure out
              the required modules.
            </para>
          </note>
        </listitem>
        <listitem>
          <para>
            Do the installation:
          </para>
          <programlisting>
# nixos-install
</programlisting>
          <para>
            This will install your system based on the configuration you
            provided. If anything fails due to a configuration problem
            or any other issue (such as a network outage while
            downloading binaries from the NixOS binary cache), you can
            re-run <literal>nixos-install</literal> after fixing your
            <literal>configuration.nix</literal>.
          </para>
          <para>
            As the last step, <literal>nixos-install</literal> will ask
            you to set the password for the <literal>root</literal>
            user, e.g.
          </para>
          <programlisting>
setting root password...
New password: ***
Retype new password: ***
</programlisting>
          <note>
            <para>
              For unattended installations, it is possible to use
              <literal>nixos-install --no-root-passwd</literal> in order
              to disable the password prompt entirely.
            </para>
          </note>
        </listitem>
        <listitem>
          <para>
            If everything went well:
          </para>
          <programlisting>
# reboot
</programlisting>
        </listitem>
        <listitem>
          <para>
            You should now be able to boot into the installed NixOS. The
            GRUB boot menu shows a list of <emphasis>available
            configurations</emphasis> (initially just one). Every time
            you change the NixOS configuration (see
            <link linkend="sec-changing-config">Changing
            Configuration</link>), a new item is added to the menu. This
            allows you to easily roll back to a previous configuration
            if something goes wrong.
          </para>
          <para>
            You should log in and change the <literal>root</literal>
            password with <literal>passwd</literal>.
          </para>
          <para>
            You’ll probably want to create some user accounts as well,
            which can be done with <literal>useradd</literal>:
          </para>
          <programlisting>
$ useradd -c 'Eelco Dolstra' -m eelco
$ passwd eelco
</programlisting>
          <para>
            You may also want to install some software. This will be
            covered in <xref linkend="sec-package-management" />.
          </para>
        </listitem>
      </orderedlist>
    </section>
    <section xml:id="sec-installation-manual-summary">
      <title>Installation summary</title>
      <para>
        <anchor xml:id="sec-installation-summary" />
        <!-- legacy anchor -->
      </para>
      <para>
        To summarise, <link linkend="ex-install-sequence">Example:
        Commands for Installing NixOS on
        <literal>/dev/sda</literal></link> shows a typical sequence of
        commands for installing NixOS on an empty hard drive (here
        <literal>/dev/sda</literal>). <link linkend="ex-config">Example:
        NixOS Configuration</link> shows a corresponding configuration
        Nix expression.
      </para>
      <anchor xml:id="ex-partition-scheme-MBR" />
      <para>
        <emphasis role="strong">Example: Example partition schemes for
        NixOS on <literal>/dev/sda</literal> (MBR)</emphasis>
      </para>
      <programlisting>
# parted /dev/sda -- mklabel msdos
# parted /dev/sda -- mkpart primary 1MiB -8GiB
# parted /dev/sda -- mkpart primary linux-swap -8GiB 100%
</programlisting>
      <anchor xml:id="ex-partition-scheme-UEFI" />
      <para>
        <emphasis role="strong">Example: Example partition schemes for
        NixOS on <literal>/dev/sda</literal> (UEFI)</emphasis>
      </para>
      <programlisting>
# parted /dev/sda -- mklabel gpt
# parted /dev/sda -- mkpart primary 512MiB -8GiB
# parted /dev/sda -- mkpart primary linux-swap -8GiB 100%
# parted /dev/sda -- mkpart ESP fat32 1MiB 512MiB
# parted /dev/sda -- set 3 esp on
</programlisting>
      <anchor xml:id="ex-install-sequence" />
      <para>
        <emphasis role="strong">Example: Commands for Installing NixOS
        on <literal>/dev/sda</literal></emphasis>
      </para>
      <para>
        With a partitioned disk.
      </para>
      <programlisting>
# mkfs.ext4 -L nixos /dev/sda1
# mkswap -L swap /dev/sda2
# swapon /dev/sda2
# mkfs.fat -F 32 -n boot /dev/sda3        # (for UEFI systems only)
# mount /dev/disk/by-label/nixos /mnt
# mkdir -p /mnt/boot                      # (for UEFI systems only)
# mount /dev/disk/by-label/boot /mnt/boot # (for UEFI systems only)
# nixos-generate-config --root /mnt
# nano /mnt/etc/nixos/configuration.nix
# nixos-install
# reboot
</programlisting>
      <anchor xml:id="ex-config" />
      <para>
        <emphasis role="strong">Example: NixOS Configuration</emphasis>
      </para>
      <programlisting>
{ config, pkgs, ... }: {
  imports = [
    # Include the results of the hardware scan.
    ./hardware-configuration.nix
  ];

  boot.loader.grub.device = &quot;/dev/sda&quot;;   # (for BIOS systems only)
  boot.loader.systemd-boot.enable = true; # (for UEFI systems only)

  # Note: setting fileSystems is generally not
  # necessary, since nixos-generate-config figures them out
  # automatically in hardware-configuration.nix.
  #fileSystems.&quot;/&quot;.device = &quot;/dev/disk/by-label/nixos&quot;;

  # Enable the OpenSSH server.
  services.sshd.enable = true;
}
</programlisting>
    </section>
  </section>
  <section xml:id="sec-installation-additional-notes">
    <title>Additional installation notes</title>
    <xi:include href="installing-usb.section.xml" />
    <xi:include href="installing-pxe.section.xml" />
    <xi:include href="installing-virtualbox-guest.section.xml" />
    <xi:include href="installing-from-other-distro.section.xml" />
    <xi:include href="installing-behind-a-proxy.section.xml" />
  </section>
</chapter>
