* Documented common environment variables.

This commit is contained in:
Eelco Dolstra 2005-03-16 16:45:29 +00:00
parent f982df3cd7
commit ad3121a52d
8 changed files with 313 additions and 180 deletions

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@ -18,7 +18,7 @@ MANUAL_SRCS = manual.xml introduction.xml installation.xml \
build-farm.xml \
$(man1_MANS:.1=.xml) \
troubleshooting.xml bugs.xml opt-common.xml opt-common-syn.xml \
quick-start.xml nix-lang-ref.xml style.css images
env-common.xml quick-start.xml nix-lang-ref.xml style.css images
manual.is-valid: $(MANUAL_SRCS) version.txt
$(XMLLINT) --xinclude $< | $(XMLLINT) --noout --valid -

112
doc/manual/env-common.xml Normal file
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@ -0,0 +1,112 @@
<sect1 id="sec-common-env"><title>Common environment variables</title>
<para>Most Nix commands interpret the following environment variables:</para>
<variablelist>
<varlistentry><term><envar>NIX_ROOT</envar></term>
<listitem><para>If <envar>NIX_ROOT</envar> is set, the Nix command
will on startup perform a <function>chroot()</function> to the
specified directory. This is useful in certain bootstrapping
situations (e.g., when installing a Nix installation onto a hard
disk from CD-ROM).</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 youre not going to do that, you can set
<envar>NIX_IGNORE_SYMLINK_STORE</envar> to <envar>1</envar>.</para>
<para>Note that if youre symlinking the Nix store so that you can
put it on another file system than the root file system, on Linux
youre 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>/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_DB_DIR</envar></term>
<listitem><para>Overrides the location of the Nix database (default
<filename><replaceable>$NIX_STATE_DIR</replaceable>/db</filename>, i.e.,
<filename><replaceable>prefix</replaceable>/var/nix/db</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>NIX_LOG_TYPE</envar></term>
<listitem><para>Equivalent to the <link
linkend="opt-log-type"><option>--log-type</option>
option</link>.</para></listitem>
</varlistentry>
</variablelist>
</sect1>

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@ -33,6 +33,8 @@
<appendix>
<title>Command Reference</title>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common.xml" />
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="env-common.xml" />
<sect1>
<title>nix-env</title>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="nix-env.xml" />

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@ -74,13 +74,12 @@
<para>
This section lists the options that are common to all
operations. These options are allowed for every subcommand,
though they may not always have an effect.
though they may not always have an effect. See also <xref
linkend="sec-common-options" />.
</para>
<variablelist>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common.xml#xpointer(/nop/*)" />
<varlistentry>
<term><option>--file</option> / <option>-f</option></term>
<listitem>

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@ -31,7 +31,8 @@
<para>
This command is generally used for testing Nix expression before
they are used with <command>nix-env</command>.
they are used with <command>nix-env</command>. See also <xref
linkend="sec-common-options" />.
</para>
</refsection>
@ -41,8 +42,6 @@
<variablelist>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common.xml#xpointer(/nop/*)" />
<varlistentry>
<term><option>--parse-only</option></term>
<listitem>

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@ -41,15 +41,10 @@
<para>
This section lists the options that are common to all
operations. These options are allowed for every subcommand,
though they may not always have an effect.
though they may not always have an effect. See also <xref
linkend="sec-common-options" />.
</para>
<variablelist>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common.xml#xpointer(/nop/*)" />
</variablelist>
</refsection>

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@ -1,188 +1,209 @@
<nop>
<sect1 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>
<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><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> / <option>-v</option></term>
<varlistentry><term><option>--verbose</option> / <option>-v</option></term>
<listitem>
<para>
Increases the level of verbosity of diagnostic messages printed
on standard error. For each Nix operation, the information
<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>
output.</para>
<para>
This option may be specified repeatedly. Currently, the
following verbosity levels exist:
</para>
<para>This option may be specified repeatedly. Currently, the
following verbosity levels exist:</para>
<variablelist>
<varlistentry>
<term>0</term>
<listitem>
<para>
<quote>Errors only</quote>: only print messages explaining
why the Nix invocation failed.
</para>
</listitem>
<varlistentry><term>0</term>
<listitem><para><quote>Errors only</quote>: only print messages
explaining why the Nix invocation failed.</para></listitem>
</varlistentry>
<varlistentry>
<term>1</term>
<listitem>
<para>
<quote>Informational</quote>: print
<emphasis>useful</emphasis> messages about what Nix is
doing. This is the default.
</para>
</listitem>
<varlistentry><term>1</term>
<listitem><para><quote>Informational</quote>: print
<emphasis>useful</emphasis> messages about what Nix is doing.
This is the default.</para></listitem>
</varlistentry>
<varlistentry>
<term>2</term>
<listitem>
<para>
<quote>Talkative</quote>: print more informational messages.
</para>
</listitem>
<varlistentry><term>2</term>
<listitem><para><quote>Talkative</quote>: print more informational
messages.</para></listitem>
</varlistentry>
<varlistentry>
<term>3</term>
<listitem>
<para>
<quote>Chatty</quote>: print even more informational messages.
</para>
</listitem>
<varlistentry><term>3</term>
<listitem><para><quote>Chatty</quote>: print even more
informational messages.</para></listitem>
</varlistentry>
<varlistentry>
<term>4</term>
<listitem>
<para>
<quote>Debug</quote>: print debug information:
</para>
</listitem>
<varlistentry><term>4</term>
<listitem><para><quote>Debug</quote>: print debug
information.</para></listitem>
</varlistentry>
<varlistentry>
<term>5</term>
<listitem>
<para>
<quote>Vomit</quote>: print vast amounts of debug
information.
</para>
</listitem>
<varlistentry><term>5</term>
<listitem><para><quote>Vomit</quote>: print vast amounts of debug
information.</para></listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-build-output</option> / <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><term><option>--no-build-output</option> / <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>
<term><option>--max-jobs</option> / <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 1. A higher
value is useful on SMP systems or to exploit I/O latency.
</para>
</listitem>
<varlistentry><term><option>--max-jobs</option> / <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 1. A
higher value is useful on SMP systems or to exploit I/O latency.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--keep-going</option> / <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
<varlistentry><term><option>--keep-going</option> / <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>
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> / <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
<varlistentry><term><option>--keep-failed</option> / <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 realise a derivation for which a
closure is already known, but this closure cannot be realised,
fall back on normalising the derivation.
</para>
<varlistentry><term><option>--fallback</option></term>
<para>
The most common scenario in which this is useful is when we have
registered substitutes in order to perform binary distribution
<listitem>
<para>Whenever Nix attempts to realise a derivation for which a
closure is already known, but this closure cannot be realised, fall
back on normalising 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,
binary installation falls back on a source installation. 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>
specified, Nix will build the derivation instead. Thus, binary
installation falls back on a source installation. 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>
<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 id="opt-log-type"><term><option>--log-type</option>
<replaceable>type</replaceable></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>This option determines how the output written to standard
error is formatted. Nixs 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>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>
</nop>
</variablelist>
</sect1>

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