mirror of
https://github.com/privatevoid-net/nix-super.git
synced 2024-11-27 00:06:16 +02:00
f2c3fc5191
NixOS evaluation errors in particular look intimidating and generally aren't very useful. Ideally the builtins.throw messages should be self-contained.
319 lines
11 KiB
XML
319 lines
11 KiB
XML
<section 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>
|
||
|
||
<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-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><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 nstallation 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>In <command>nix-env</command>,
|
||
<command>nix-instantiate</command> and <command>nix-build</command>,
|
||
<option>--attr</option> allows you to select an attribute from the
|
||
top-level Nix expression being evaluated. 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>--show-trace</option></term>
|
||
|
||
<listitem><para>Causes Nix to print out a stack trace in case of Nix
|
||
expression evaluation errors.</para></listitem>
|
||
|
||
</varlistentry>
|
||
|
||
|
||
</variablelist>
|
||
|
||
|
||
</section>
|