a574065a81
‘nixos-rebuild dry-activate’ builds the new configuration and then prints what systemd services would be stopped, restarted etc. if the configuration were actually activated. This could be extended later to show other activation actions (like uids being deleted). To prevent confusion, ‘nixos-rebuild dry-run’ has been renamed to ‘nixos-rebuild dry-build’.
348 lines
12 KiB
XML
348 lines
12 KiB
XML
<refentry xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude">
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<refmeta>
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<refentrytitle><command>nixos-rebuild</command></refentrytitle>
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<manvolnum>8</manvolnum>
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<refmiscinfo class="source">NixOS</refmiscinfo>
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<!-- <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo> -->
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</refmeta>
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<refnamediv>
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<refname><command>nixos-rebuild</command></refname>
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<refpurpose>reconfigure a NixOS machine</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<cmdsynopsis>
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<command>nixos-rebuild</command>
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<group choice='req'>
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<arg choice='plain'><option>switch</option></arg>
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<arg choice='plain'><option>boot</option></arg>
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<arg choice='plain'><option>test</option></arg>
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<arg choice='plain'><option>build</option></arg>
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<arg choice='plain'><option>dry-build</option></arg>
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<arg choice='plain'><option>dry-activate</option></arg>
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<arg choice='plain'><option>build-vm</option></arg>
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<arg choice='plain'><option>build-vm-with-bootloader</option></arg>
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</group>
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<sbr />
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<arg><option>--upgrade</option></arg>
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<arg><option>--install-grub</option></arg>
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<arg><option>--no-build-nix</option></arg>
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<arg><option>--fast</option></arg>
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<arg><option>--rollback</option></arg>
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<sbr />
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<arg>
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<group choice='req'>
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<arg choice='plain'><option>--profile-name</option></arg>
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<arg choice='plain'><option>-p</option></arg>
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</group>
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<replaceable>name</replaceable>
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</arg>
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<sbr />
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<arg><option>--show-trace</option></arg>
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</cmdsynopsis>
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</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
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configuration specified in
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<filename>/etc/nixos/configuration.nix</filename>. Thus, every time
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you modify <filename>/etc/nixos/configuration.nix</filename> or any
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NixOS module, you must run <command>nixos-rebuild</command> to make
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the changes take effect. It builds the new system in
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<filename>/nix/store</filename>, runs its activation script, and stop
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and (re)starts any system services if needed.</para>
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<para>This command has one required argument, which specifies the
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desired operation. It must be one of the following:
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<variablelist>
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<varlistentry>
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<term><option>switch</option></term>
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<listitem>
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<para>Build and activate the new configuration, and make it the
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boot default. That is, the configuration is added to the GRUB
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boot menu as the default meny entry, so that subsequent reboots
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will boot the system into the new configuration. Previous
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configurations activated with <command>nixos-rebuild
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switch</command> or <command>nixos-rebuild boot</command> remain
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available in the GRUB menu.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>boot</option></term>
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<listitem>
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<para>Build the new configuration and make it the boot default
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(as with <command>nixos-rebuild switch</command>), but do not
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activate it. That is, the system continues to run the previous
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configuration until the next reboot.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>test</option></term>
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<listitem>
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<para>Build and activate the new configuration, but do not add
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it to the GRUB boot menu. Thus, if you reboot the system (or if
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it crashes), you will automatically revert to the default
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configuration (i.e. the configuration resulting from the last
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call to <command>nixos-rebuild switch</command> or
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<command>nixos-rebuild boot</command>).</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>build</option></term>
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<listitem>
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<para>Build the new configuration, but neither activate it nor
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add it to the GRUB boot menu. It leaves a symlink named
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<filename>result</filename> in the current directory, which
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points to the output of the top-level “system” derivation. This
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is essentially the same as doing
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<screen>
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$ nix-build /path/to/nixpkgs/nixos -A system
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</screen>
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Note that you do not need to be <literal>root</literal> to run
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<command>nixos-rebuild build</command>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>dry-build</option></term>
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<listitem>
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<para>Show what store paths would be built or downloaded by any
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of the operations above, but otherwise do nothing.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>dry-activate</option></term>
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<listitem>
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<para>Build the new configuration, but instead of activating it,
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show what changes would be performed by the activation (i.e. by
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<command>nixos-rebuild test</command>). For
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instance, this command will print which systemd units would be
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restarted. The list of changes is not guaranteed to be
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complete.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>build-vm</option></term>
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<listitem>
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<para>Build a script that starts a NixOS virtual machine with
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the desired configuration. It leaves a symlink
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<filename>result</filename> in the current directory that points
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(under
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<filename>result/bin/run-<replaceable>hostname</replaceable>-vm</filename>)
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at the script that starts the VM. Thus, to test a NixOS
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configuration in a virtual machine, you should do the following:
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<screen>
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$ nixos-rebuild build-vm
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$ ./result/bin/run-*-vm
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</screen></para>
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<para>The VM is implemented using the <literal>qemu</literal>
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package. For best performance, you should load the
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<literal>kvm-intel</literal> or <literal>kvm-amd</literal>
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kernel modules to get hardware virtualisation.</para>
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<para>The VM mounts the Nix store of the host through the 9P
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file system. The host Nix store is read-only, so Nix commands
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that modify the Nix store will not work in the VM. This
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includes commands such as <command>nixos-rebuild</command>; to
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change the VM’s configuration, you must halt the VM and re-run
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the commands above.
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</para>
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<para>The VM has its own <literal>ext3</literal> root file
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system, which is automatically created when the VM is first
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started, and is persistent across reboots of the VM. It is
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stored in
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<literal>./<replaceable>hostname</replaceable>.qcow2</literal>.
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<!-- The entire file system hierarchy of the host is available in
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the VM under <filename>/hostfs</filename>.--></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>build-vm-with-bootloader</option></term>
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<listitem>
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<para>Like <option>build-vm</option>, but boots using the
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regular boot loader of your configuration (e.g., GRUB 1 or 2),
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rather than booting directly into the kernel and initial ramdisk
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of the system. This allows you to test whether the boot loader
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works correctly. However, it does not guarantee that your NixOS
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configuration will boot successfully on the host hardware (i.e.,
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after running <command>nixos-rebuild switch</command>), because
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the hardware and boot loader configuration in the VM are
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different. The boot loader is installed on an automatically
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generated virtual disk containing a <filename>/boot</filename>
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partition, which is mounted read-only in the VM.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsection>
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<refsection><title>Options</title>
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<para>This command accepts the following options:</para>
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<variablelist>
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<varlistentry>
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<term><option>--upgrade</option></term>
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<listitem>
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<para>Fetch the latest version of NixOS from the NixOS
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channel.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--install-grub</option></term>
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<listitem>
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<para>Causes the GRUB boot loader to be (re)installed on the
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device specified by the
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<varname>boot.loader.grub.device</varname> configuration
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option.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--no-build-nix</option></term>
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<listitem>
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<para>Normally, <command>nixos-rebuild</command> first builds
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the <varname>nixUnstable</varname> attribute in Nixpkgs, and
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uses the resulting instance of the Nix package manager to build
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the new system configuration. This is necessary if the NixOS
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modules use features not provided by the currently installed
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version of Nix. This option disables building a new Nix.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--fast</option></term>
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<listitem>
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<para>Equivalent to <option>--no-build-nix</option>
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<option>--show-trace</option>. This option is useful if you
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call <command>nixos-rebuild</command> frequently (e.g. if you’re
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hacking on a NixOS module).</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--rollback</option></term>
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<listitem>
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<para>Instead of building a new configuration as specified by
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<filename>/etc/nixos/configuration.nix</filename>, roll back to
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the previous configuration. (The previous configuration is
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defined as the one before the “current” generation of the
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Nix profile <filename>/nix/var/nix/profiles/system</filename>.)</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--profile-name</option></term>
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<term><option>-p</option></term>
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<listitem>
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<para>Instead of using the Nix profile
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<filename>/nix/var/nix/profiles/system</filename> to keep track
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of the current and previous system configurations, use
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<filename>/nix/var/nix/profiles/system-profiles/<replaceable>name</replaceable></filename>.
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When you use GRUB 2, for every system profile created with this
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flag, NixOS will create a submenu named “NixOS - Profile
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'<replaceable>name</replaceable>'” in GRUB’s boot menu,
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containing the current and previous configurations of this
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profile.</para>
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<para>For instance, if you want to test a configuration file
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named <filename>test.nix</filename> without affecting the
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default system profile, you would do:
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<screen>
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$ nixos-rebuild switch -p test -I nixos-config=./test.nix
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</screen>
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The new configuration will appear in the GRUB 2 submenu “NixOS - Profile
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'test'”.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<para>In addition, <command>nixos-rebuild</command> accepts various
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Nix-related flags, including <option>--max-jobs</option> /
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<option>-j</option>, <option>--show-trace</option>,
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<option>--keep-failed</option>, <option>--keep-going</option> and
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<option>--verbose</option> / <option>-v</option>. See
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the Nix manual for details.</para>
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</refsection>
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<refsection><title>Environment</title>
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<variablelist>
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<varlistentry>
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<term><envar>NIXOS_CONFIG</envar></term>
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<listitem>
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<para>Path to the main NixOS configuration module. Defaults to
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<filename>/etc/nixos/configuration.nix</filename>.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsection>
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<refsection><title>Files</title>
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<variablelist>
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<varlistentry>
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<term><filename>/run/current-system</filename></term>
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<listitem>
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<para>A symlink to the currently active system configuration in
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the Nix store.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>/nix/var/nix/profiles/system</filename></term>
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<listitem>
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<para>The Nix profile that contains the current and previous
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system configurations. Used to generate the GRUB boot
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menu.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsection>
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<refsection><title>Bugs</title>
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<para>This command should be renamed to something more
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descriptive.</para>
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</refsection>
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</refentry>
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