man-nixos-rebuild.xml: Improve layout

nixos/doc/manual/man-nixos-rebuild.xml

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   <refmiscinfo class="source">NixOS</refmiscinfo>
 <!-- <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo> -->
  </refmeta>
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  <refnamediv>
   <refname><command>nixos-rebuild</command>
   </refname><refpurpose>reconfigure a NixOS machine</refpurpose>
  </refnamediv>
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  <refsynopsisdiv>
   <cmdsynopsis>
    <command>nixos-rebuild</command><group choice='req'>
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    <arg>
     <option>--builders</option> <replaceable>builder-spec</replaceable>
    </arg>
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    <sbr />
    <arg>
     <group choice='req'>
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    </arg>
   </cmdsynopsis>
  </refsynopsisdiv>
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  <refsection>
   <title>Description</title>
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   <para>
    This command updates the system so that it corresponds to the configuration
    specified in <filename>/etc/nixos/configuration.nix</filename>. Thus, every
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    (re)starts any system services if needed. Please note that user services need
    to be started manually as they aren't detected by the activation script at the moment.
   </para>
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   <para>
    This command has one required argument, which specifies the desired
    operation. It must be one of the following:
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    <variablelist>
     <varlistentry>
      <term>
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>boot</option>
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>test</option>
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>build</option>
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>dry-build</option>
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>dry-activate</option>
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>edit</option>
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>build-vm</option>
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 <prompt>$ </prompt>./result/bin/run-*-vm
 </screen>
       </para>
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       <para>
        The VM is implemented using the <literal>qemu</literal> package. For
        best performance, you should load the <literal>kvm-intel</literal> or
        <literal>kvm-amd</literal> kernel modules to get hardware
        virtualisation.
       </para>
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       <para>
        The VM mounts the Nix store of the host through the 9P file system. The
        host Nix store is read-only, so Nix commands that modify the Nix store
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        <command>nixos-rebuild</command>; to change the VM’s configuration,
        you must halt the VM and re-run the commands above.
       </para>
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       <para>
        The VM has its own <literal>ext3</literal> root file system, which is
        automatically created when the VM is first started, and is persistent
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       </para>
      </listitem>
     </varlistentry>
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     <varlistentry>
      <term>
       <option>build-vm-with-bootloader</option>
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    </variablelist>
   </para>
  </refsection>
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  <refsection>
   <title>Options</title>
   <para>
    This command accepts the following options:
   </para>
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   <variablelist>
    <varlistentry>
     <term>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--install-bootloader</option>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--no-build-nix</option>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--fast</option>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--rollback</option>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--builders</option> <replaceable>builder-spec</replaceable>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--profile-name</option>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--build-host</option>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <option>--target-host</option>
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       be accessible over ssh, and for the commands <option>switch</option>,
       <option>boot</option> and <option>test</option> you need root access.
      </para>
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      <para>
       If <option>--build-host</option> is not explicitly specified,
       <option>--build-host</option> will implicitly be set to the same value as
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       place remotely (and no build artifacts will be copied to the local
       machine).
      </para>
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      <para>
       You can include a remote user name in the host name
       (<replaceable>user@host</replaceable>). You can also set ssh options by
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     </listitem>
    </varlistentry>
   </variablelist>
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   <para>
    In addition, <command>nixos-rebuild</command> accepts various Nix-related
    flags, including <option>--max-jobs</option> / <option>-j</option>,
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    <option>-v</option>. See the Nix manual for details.
   </para>
  </refsection>
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  <refsection>
   <title>Environment</title>
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   <variablelist>
    <varlistentry>
     <term>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <envar>NIX_SSHOPTS</envar>
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    </varlistentry>
   </variablelist>
  </refsection>
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  <refsection>
   <title>Files</title>
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   <variablelist>
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    <varlistentry>
     <term>
      <filename>/run/current-system</filename>
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      </para>
     </listitem>
    </varlistentry>
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    <varlistentry>
     <term>
      <filename>/nix/var/nix/profiles/system</filename>
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      </para>
     </listitem>
    </varlistentry>
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   </variablelist>
  </refsection>
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  <refsection>
   <title>Bugs</title>
   <para>