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diff --git a/doc/manual/command-ref/opt-common.xml b/doc/manual/command-ref/opt-common.xml new file mode 100644 index 000000000000..c7e8ae1ed05f --- /dev/null +++ b/doc/manual/command-ref/opt-common.xml @@ -0,0 +1,390 @@ +<chapter xmlns="http://docbook.org/ns/docbook" xml:id="sec-common-options"> + +<title>Common Options</title> + + +<para>Most Nix commands accept the following command-line options:</para> + +<variablelist xml:id="opt-common"> + +<varlistentry><term><option>--help</option></term> + + <listitem><para>Prints out a summary of the command syntax and + exits.</para></listitem> + +</varlistentry> + + +<varlistentry><term><option>--version</option></term> + + <listitem><para>Prints out the Nix version number on standard output + and exits.</para></listitem> +</varlistentry> + + +<varlistentry><term><option>--verbose</option></term> + <term><option>-v</option></term> + + <listitem> + + <para>Increases the level of verbosity of diagnostic messages + printed on standard error. For each Nix operation, the information + printed on standard output is well-defined; any diagnostic + information is printed on standard error, never on standard + output.</para> + + <para>This option may be specified repeatedly. Currently, the + following verbosity levels exist:</para> + + <variablelist> + + <varlistentry><term>0</term> + <listitem><para>“Errors only”: only print messages + explaining why the Nix invocation failed.</para></listitem> + </varlistentry> + + <varlistentry><term>1</term> + <listitem><para>“Informational”: print + <emphasis>useful</emphasis> messages about what Nix is doing. + This is the default.</para></listitem> + </varlistentry> + + <varlistentry><term>2</term> + <listitem><para>“Talkative”: print more informational + messages.</para></listitem> + </varlistentry> + + <varlistentry><term>3</term> + <listitem><para>“Chatty”: print even more + informational messages.</para></listitem> + </varlistentry> + + <varlistentry><term>4</term> + <listitem><para>“Debug”: print debug + information.</para></listitem> + </varlistentry> + + <varlistentry><term>5</term> + <listitem><para>“Vomit”: print vast amounts of debug + information.</para></listitem> + </varlistentry> + + </variablelist> + + </listitem> + +</varlistentry> + + +<varlistentry><term><option>--no-build-output</option></term> + <term><option>-Q</option></term> + + <listitem><para>By default, output written by builders to standard + output and standard error is echoed to the Nix command's standard + error. This option suppresses this behaviour. Note that the + builder's standard output and error are always written to a log file + in + <filename><replaceable>prefix</replaceable>/nix/var/log/nix</filename>.</para></listitem> + +</varlistentry> + + +<varlistentry xml:id="opt-max-jobs"><term><option>--max-jobs</option></term> + <term><option>-j</option></term> + + <listitem><para>Sets the maximum number of build jobs that Nix will + perform in parallel to the specified number. The default is + specified by the <link + linkend='conf-build-max-jobs'><literal>build-max-jobs</literal></link> + configuration setting, which itself defaults to + <literal>1</literal>. A higher value is useful on SMP systems or to + exploit I/O latency.</para></listitem> + +</varlistentry> + + +<varlistentry xml:id="opt-cores"><term><option>--cores</option></term> + + <listitem><para>Sets the value of the <envar>NIX_BUILD_CORES</envar> + environment variable in the invocation of builders. Builders can + use this variable at their discretion to control the maximum amount + of parallelism. For instance, in Nixpkgs, if the derivation + attribute <varname>enableParallelBuilding</varname> is set to + <literal>true</literal>, the builder passes the + <option>-j<replaceable>N</replaceable></option> flag to GNU Make. + It defaults to the value of the <link + linkend='conf-build-cores'><literal>build-cores</literal></link> + configuration setting, if set, or <literal>1</literal> otherwise. + The value <literal>0</literal> means that the builder should use all + available CPU cores in the system.</para></listitem> + +</varlistentry> + + +<varlistentry xml:id="opt-max-silent-time"><term><option>--max-silent-time</option></term> + + <listitem><para>Sets the maximum number of seconds that a builder + can go without producing any data on standard output or standard + error. The default is specified by the <link + linkend='conf-build-max-silent-time'><literal>build-max-silent-time</literal></link> + configuration setting. <literal>0</literal> means no + time-out.</para></listitem> + +</varlistentry> + +<varlistentry xml:id="opt-timeout"><term><option>--timeout</option></term> + + <listitem><para>Sets the maximum number of seconds that a builder + can run. The default is specified by the <link + linkend='conf-build-timeout'><literal>build-timeout</literal></link> + configuration setting. <literal>0</literal> means no + timeout.</para></listitem> + +</varlistentry> + +<varlistentry><term><option>--keep-going</option></term> + <term><option>-k</option></term> + + <listitem><para>Keep going in case of failed builds, to the + greatest extent possible. That is, if building an input of some + derivation fails, Nix will still build the other inputs, but not the + derivation itself. Without this option, Nix stops if any build + fails (except for builds of substitutes), possibly killing builds in + progress (in case of parallel or distributed builds).</para></listitem> + +</varlistentry> + + +<varlistentry><term><option>--keep-failed</option></term> + <term><option>-K</option></term> + + <listitem><para>Specifies that in case of a build failure, the + temporary directory (usually in <filename>/tmp</filename>) in which + the build takes place should not be deleted. The path of the build + directory is printed as an informational message. + </para> + </listitem> +</varlistentry> + + +<varlistentry><term><option>--fallback</option></term> + + <listitem> + + <para>Whenever Nix attempts to build a derivation for which + substitutes are known for each output path, but realising the output + paths through the substitutes fails, fall back on building the + derivation.</para> + + <para>The most common scenario in which this is useful is when we + have registered substitutes in order to perform binary distribution + from, say, a network repository. If the repository is down, the + realisation of the derivation will fail. When this option is + specified, Nix will build the derivation instead. Thus, + installation from binaries falls back on installation from source. + This option is not the default since it is generally not desirable + for a transient failure in obtaining the substitutes to lead to a + full build from source (with the related consumption of + resources).</para> + + </listitem> + +</varlistentry> + + +<varlistentry><term><option>--readonly-mode</option></term> + + <listitem><para>When this option is used, no attempt is made to open + the Nix database. Most Nix operations do need database access, so + those operations will fail.</para></listitem> + +</varlistentry> + + +<varlistentry xml:id="opt-log-type"><term><option>--log-type</option> +<replaceable>type</replaceable></term> + + <listitem> + + <para>This option determines how the output written to standard + error is formatted. Nix’s diagnostic messages are typically + <emphasis>nested</emphasis>. For instance, when tracing Nix + expression evaluation (<command>nix-env -vvvvv</command>, messages + from subexpressions are nested inside their parent expressions. Nix + builder output is also often nested. For instance, the Nix Packages + generic builder nests the various build tasks (unpack, configure, + compile, etc.), and the GNU Make in <literal>stdenv-linux</literal> + has been patched to provide nesting for recursive Make + invocations.</para> + + <para><replaceable>type</replaceable> can be one of the + following: + + <variablelist> + + <varlistentry><term><literal>pretty</literal></term> + + <listitem><para>Pretty-print the output, indicating different + nesting levels using spaces. This is the + default.</para></listitem> + + </varlistentry> + + <varlistentry><term><literal>escapes</literal></term> + + <listitem><para>Indicate nesting using escape codes that can be + interpreted by the <command>nix-log2xml</command> tool in the + Nix source distribution. The resulting XML file can be fed into + the <command>log2html.xsl</command> stylesheet to create an HTML + file that can be browsed interactively, using JavaScript to + expand and collapse parts of the output.</para></listitem> + + </varlistentry> + + <varlistentry><term><literal>flat</literal></term> + + <listitem><para>Remove all nesting.</para></listitem> + + </varlistentry> + + </variablelist> + + </para> + + </listitem> + +</varlistentry> + + +<varlistentry><term><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></term> + + <listitem><para>This option is accepted by + <command>nix-env</command>, <command>nix-instantiate</command> and + <command>nix-build</command>. When evaluating Nix expressions, the + expression evaluator will automatically try to call functions that + it encounters. It can automatically call functions for which every + argument has a <link linkend='ss-functions'>default value</link> + (e.g., <literal>{ <replaceable>argName</replaceable> ? + <replaceable>defaultValue</replaceable> }: + <replaceable>...</replaceable></literal>). With + <option>--arg</option>, you can also call functions that have + arguments without a default value (or override a default value). + That is, if the evaluator encounters a function with an argument + named <replaceable>name</replaceable>, it will call it with value + <replaceable>value</replaceable>.</para> + + <para>For instance, the file + <literal>pkgs/top-level/all-packages.nix</literal> in Nixpkgs is + actually a function: + +<programlisting> +{ # The system (e.g., `i686-linux') for which to build the packages. + system ? builtins.currentSystem + <replaceable>...</replaceable> +}: <replaceable>...</replaceable></programlisting> + + So if you call this Nix expression (e.g., when you do + <literal>nix-env -i <replaceable>pkgname</replaceable></literal>), + the function will be called automatically using the value <link + linkend='builtin-currentSystem'><literal>builtins.currentSystem</literal></link> + for the <literal>system</literal> argument. You can override this + using <option>--arg</option>, e.g., <literal>nix-env -i + <replaceable>pkgname</replaceable> --arg system + \"i686-freebsd\"</literal>. (Note that since the argument is a Nix + string literal, you have to escape the quotes.)</para></listitem> + +</varlistentry> + + +<varlistentry><term><option>--argstr</option> <replaceable>name</replaceable> <replaceable>value</replaceable></term> + + <listitem><para>This option is like <option>--arg</option>, only the + value is not a Nix expression but a string. So instead of + <literal>--arg system \"i686-linux\"</literal> (the outer quotes are + to keep the shell happy) you can say <literal>--argstr system + i686-linux</literal>.</para></listitem> + +</varlistentry> + + +<varlistentry xml:id="opt-attr"><term><option>--attr</option> / <option>-A</option> +<replaceable>attrPath</replaceable></term> + + <listitem><para>Select an attribute from the top-level Nix + expression being evaluated. (<command>nix-env</command>, + <command>nix-instantiate</command>, <command>nix-build</command> and + <command>nix-shell</command> only.) The <emphasis>attribute + path</emphasis> <replaceable>attrPath</replaceable> is a sequence of + attribute names separated by dots. For instance, given a top-level + Nix expression <replaceable>e</replaceable>, the attribute path + <literal>xorg.xorgserver</literal> would cause the expression + <literal><replaceable>e</replaceable>.xorg.xorgserver</literal> to + be used. See <link + linkend='refsec-nix-env-install-examples'><command>nix-env + --install</command></link> for some concrete examples.</para> + + <para>In addition to attribute names, you can also specify array + indices. For instance, the attribute path + <literal>foo.3.bar</literal> selects the <literal>bar</literal> + attribute of the fourth element of the array in the + <literal>foo</literal> attribute of the top-level + expression.</para></listitem> + +</varlistentry> + + +<varlistentry><term><option>--expr</option> / <option>-E</option></term> + + <listitem><para>Interpret the command line arguments as a list of + Nix expressions to be parsed and evaluated, rather than as a list + of file names of Nix expressions. + (<command>nix-instantiate</command>, <command>nix-build</command> + and <command>nix-shell</command> only.)</para></listitem> + +</varlistentry> + +<varlistentry><term><option>--show-trace</option></term> + + <listitem><para>Causes Nix to print out a stack trace in case of Nix + expression evaluation errors.</para></listitem> + +</varlistentry> + + +<varlistentry xml:id="opt-I"><term><option>-I</option> <replaceable>path</replaceable></term> + + <listitem><para>Add a path to the Nix expression search path. This + option may be given multiple times. See the <envar + linkend="env-NIX_PATH">NIX_PATH</envar> environment variable for + information on the semantics of the Nix search path. Paths added + through <option>-I</option> take precedence over + <envar>NIX_PATH</envar>.</para></listitem> + +</varlistentry> + + +<varlistentry><term><option>--option</option> <replaceable>name</replaceable> <replaceable>value</replaceable></term> + + <listitem><para>Set the Nix configuration option + <replaceable>name</replaceable> to <replaceable>value</replaceable>. + This overrides settings in the Nix configuration file (see + <citerefentry><refentrytitle>nix.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).</para></listitem> + +</varlistentry> + + +<varlistentry><term><option>--repair</option></term> + + <listitem><para>Fix corrupted or missing store paths by + redownloading or rebuilding them. Note that this is slow because it + requires computing a cryptographic hash of the contents of every + path in the closure of the build. Also note the warning under + <command>nix-store --repair-path</command>.</para></listitem> + +</varlistentry> + + +</variablelist> + + +</chapter> |