112 lines
3.4 KiB
XML
112 lines
3.4 KiB
XML
<sect1 id="sec-common-env"><title>Common environment variables</title>
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<para>Most Nix commands interpret the following environment variables:</para>
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<variablelist>
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<varlistentry><term><envar>NIX_ROOT</envar></term>
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<listitem><para>If <envar>NIX_ROOT</envar> is set, the Nix command
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will on startup perform a <function>chroot()</function> to the
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specified directory. This is useful in certain bootstrapping
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situations (e.g., when installing a Nix installation onto a hard
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disk from CD-ROM).</para></listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_IGNORE_SYMLINK_STORE</envar></term>
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<listitem>
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<para>Normally, the Nix store directory (typically
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<filename>/nix/store</filename>) is not allowed to contain any
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symlink components. This is to prevent “impure” builds. Builders
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sometimes “canonicalise” paths by resolving all symlink components.
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Thus, builds on different machines (with
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<filename>/nix/store</filename> resolving to different locations)
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could yield different results. This is generally not a problem,
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except when builds are deployed to machines where
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<filename>/nix/store</filename> resolves differently. If you are
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sure that you’re not going to do that, you can set
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<envar>NIX_IGNORE_SYMLINK_STORE</envar> to <envar>1</envar>.</para>
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<para>Note that if you’re symlinking the Nix store so that you can
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put it on another file system than the root file system, on Linux
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you’re better off using <literal>bind</literal> mount points, e.g.,
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<screen>
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$ mkdir /nix
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$ mount -o bind /mnt/otherdisk/nix /nix</screen>
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Consult the <citerefentry><refentrytitle>mount</refentrytitle>
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<manvolnum>8</manvolnum></citerefentry> manual page for details.</para>
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</listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_STORE_DIR</envar></term>
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<listitem><para>Overrides the location of the Nix store (default
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<filename><replaceable>prefix</replaceable>/store</filename>).</para></listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_DATA_DIR</envar></term>
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<listitem><para>Overrides the location of the Nix static data
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directory (default
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<filename><replaceable>prefix</replaceable>/share</filename>).</para></listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_LOG_DIR</envar></term>
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<listitem><para>Overrides the location of the Nix log directory
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(default <filename><replaceable>prefix</replaceable>/log/nix</filename>).</para></listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_STATE_DIR</envar></term>
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<listitem><para>Overrides the location of the Nix state directory
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(default <filename><replaceable>prefix</replaceable>/var/nix</filename>).</para></listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_DB_DIR</envar></term>
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<listitem><para>Overrides the location of the Nix database (default
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<filename><replaceable>$NIX_STATE_DIR</replaceable>/db</filename>, i.e.,
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<filename><replaceable>prefix</replaceable>/var/nix/db</filename>).</para></listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_CONF_DIR</envar></term>
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<listitem><para>Overrides the location of the Nix configuration
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directory (default
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<filename><replaceable>prefix</replaceable>/etc/nix</filename>).</para></listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_LOG_TYPE</envar></term>
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<listitem><para>Equivalent to the <link
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linkend="opt-log-type"><option>--log-type</option>
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option</link>.</para></listitem>
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</varlistentry>
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</variablelist>
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</sect1>
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