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diff --git a/third_party/nix/doc/manual/command-ref/env-common.xml b/third_party/nix/doc/manual/command-ref/env-common.xml new file mode 100644 index 000000000000..696d68c34516 --- /dev/null +++ b/third_party/nix/doc/manual/command-ref/env-common.xml @@ -0,0 +1,202 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-common-env"> + +<title>Common Environment Variables</title> + + +<para>Most Nix commands interpret the following environment variables:</para> + +<variablelist xml:id="env-common"> + +<varlistentry><term><envar>IN_NIX_SHELL</envar></term> + + <listitem><para>Indicator that tells if the current environment was set up by + <command>nix-shell</command>. Since Nix 2.0 the values are + <literal>"pure"</literal> and <literal>"impure"</literal></para></listitem> + +</varlistentry> + +<varlistentry xml:id="env-NIX_PATH"><term><envar>NIX_PATH</envar></term> + + <listitem> + + <para>A colon-separated list of directories used to look up Nix + expressions enclosed in angle brackets (i.e., + <literal><<replaceable>path</replaceable>></literal>). For + instance, the value + + <screen> +/home/eelco/Dev:/etc/nixos</screen> + + will cause Nix to look for paths relative to + <filename>/home/eelco/Dev</filename> and + <filename>/etc/nixos</filename>, in that order. It is also + possible to match paths against a prefix. For example, the value + + <screen> +nixpkgs=/home/eelco/Dev/nixpkgs-branch:/etc/nixos</screen> + + will cause Nix to search for + <literal><nixpkgs/<replaceable>path</replaceable>></literal> in + <filename>/home/eelco/Dev/nixpkgs-branch/<replaceable>path</replaceable></filename> + and + <filename>/etc/nixos/nixpkgs/<replaceable>path</replaceable></filename>.</para> + + <para>If a path in the Nix search path starts with + <literal>http://</literal> or <literal>https://</literal>, it is + interpreted as the URL of a tarball that will be downloaded and + unpacked to a temporary location. The tarball must consist of a + single top-level directory. For example, setting + <envar>NIX_PATH</envar> to + + <screen> +nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/nixos-15.09.tar.gz</screen> + + tells Nix to download the latest revision in the Nixpkgs/NixOS + 15.09 channel.</para> + + <para>A following shorthand can be used to refer to the official channels: + + <screen>nixpkgs=channel:nixos-15.09</screen> + </para> + + <para>The search path can be extended using the <option + linkend="opt-I">-I</option> option, which takes precedence over + <envar>NIX_PATH</envar>.</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_IGNORE_SYMLINK_STORE</envar></term> + + <listitem> + + <para>Normally, the Nix store directory (typically + <filename>/nix/store</filename>) is not allowed to contain any + symlink components. This is to prevent “impure” builds. Builders + sometimes “canonicalise” paths by resolving all symlink components. + Thus, builds on different machines (with + <filename>/nix/store</filename> resolving to different locations) + could yield different results. This is generally not a problem, + except when builds are deployed to machines where + <filename>/nix/store</filename> resolves differently. If you are + sure that you’re not going to do that, you can set + <envar>NIX_IGNORE_SYMLINK_STORE</envar> to <envar>1</envar>.</para> + + <para>Note that if you’re symlinking the Nix store so that you can + put it on another file system than the root file system, on Linux + you’re better off using <literal>bind</literal> mount points, e.g., + + <screen> +$ mkdir /nix +$ mount -o bind /mnt/otherdisk/nix /nix</screen> + + Consult the <citerefentry><refentrytitle>mount</refentrytitle> + <manvolnum>8</manvolnum></citerefentry> manual page for details.</para> + + </listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_STORE_DIR</envar></term> + + <listitem><para>Overrides the location of the Nix store (default + <filename><replaceable>prefix</replaceable>/store</filename>).</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_DATA_DIR</envar></term> + + <listitem><para>Overrides the location of the Nix static data + directory (default + <filename><replaceable>prefix</replaceable>/share</filename>).</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_LOG_DIR</envar></term> + + <listitem><para>Overrides the location of the Nix log directory + (default <filename><replaceable>prefix</replaceable>/var/log/nix</filename>).</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_STATE_DIR</envar></term> + + <listitem><para>Overrides the location of the Nix state directory + (default <filename><replaceable>prefix</replaceable>/var/nix</filename>).</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_CONF_DIR</envar></term> + + <listitem><para>Overrides the location of the Nix configuration + directory (default + <filename><replaceable>prefix</replaceable>/etc/nix</filename>).</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>TMPDIR</envar></term> + + <listitem><para>Use the specified directory to store temporary + files. In particular, this includes temporary build directories; + these can take up substantial amounts of disk space. The default is + <filename>/tmp</filename>.</para></listitem> + +</varlistentry> + + +<varlistentry xml:id="envar-remote"><term><envar>NIX_REMOTE</envar></term> + + <listitem><para>This variable should be set to + <literal>daemon</literal> if you want to use the Nix daemon to + execute Nix operations. This is necessary in <link + linkend="ssec-multi-user">multi-user Nix installations</link>. + If the Nix daemon's Unix socket is at some non-standard path, + this variable should be set to <literal>unix://path/to/socket</literal>. + Otherwise, it should be left unset.</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_SHOW_STATS</envar></term> + + <listitem><para>If set to <literal>1</literal>, Nix will print some + evaluation statistics, such as the number of values + allocated.</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>NIX_COUNT_CALLS</envar></term> + + <listitem><para>If set to <literal>1</literal>, Nix will print how + often functions were called during Nix expression evaluation. This + is useful for profiling your Nix expressions.</para></listitem> + +</varlistentry> + + +<varlistentry><term><envar>GC_INITIAL_HEAP_SIZE</envar></term> + + <listitem><para>If Nix has been configured to use the Boehm garbage + collector, this variable sets the initial size of the heap in bytes. + It defaults to 384 MiB. Setting it to a low value reduces memory + consumption, but will increase runtime due to the overhead of + garbage collection.</para></listitem> + +</varlistentry> + + +</variablelist> + + +</chapter> |