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diff --git a/doc/manual/command-ref/nix-store.xml b/doc/manual/command-ref/nix-store.xml new file mode 100644 index 000000000000..ae0f683f2c16 --- /dev/null +++ b/doc/manual/command-ref/nix-store.xml @@ -0,0 +1,1352 @@ +<refentry 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-nix-store"> + +<refmeta> + <refentrytitle>nix-store</refentrytitle> + <manvolnum>1</manvolnum> + <refmiscinfo class="source">Nix</refmiscinfo> + <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo> +</refmeta> + +<refnamediv> + <refname>nix-store</refname> + <refpurpose>manipulate or query the Nix store</refpurpose> +</refnamediv> + +<refsynopsisdiv> + <cmdsynopsis> + <command>nix-store</command> + <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(/db:nop/*)" /> + <arg><option>--add-root</option> <replaceable>path</replaceable></arg> + <arg><option>--indirect</option></arg> + <arg choice='plain'><replaceable>operation</replaceable></arg> + <arg rep='repeat'><replaceable>options</replaceable></arg> + <arg rep='repeat'><replaceable>arguments</replaceable></arg> + </cmdsynopsis> +</refsynopsisdiv> + + +<refsection><title>Description</title> + +<para>The command <command>nix-store</command> performs primitive +operations on the Nix store. You generally do not need to run this +command manually.</para> + +<para><command>nix-store</command> takes exactly one +<emphasis>operation</emphasis> flag which indicates the subcommand to +be performed. These are documented below.</para> + +</refsection> + + + +<!--######################################################################--> + +<refsection><title>Common options</title> + +<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. <phrase condition="manual">See +also <xref linkend="sec-common-options" /> for a list of common +options.</phrase></para> + +<variablelist> + + <varlistentry xml:id="opt-add-root"><term><option>--add-root</option> <replaceable>path</replaceable></term> + + <listitem><para>Causes the result of a realisation + (<option>--realise</option> and <option>--force-realise</option>) + to be registered as a root of the garbage collector<phrase + condition="manual"> (see <xref linkend="ssec-gc-roots" + />)</phrase>. The root is stored in + <replaceable>path</replaceable>, which must be inside a directory + that is scanned for roots by the garbage collector (i.e., + typically in a subdirectory of + <filename>/nix/var/nix/gcroots/</filename>) + <emphasis>unless</emphasis> the <option>--indirect</option> flag + is used.</para> + + <para>If there are multiple results, then multiple symlinks will + be created by sequentially numbering symlinks beyond the first one + (e.g., <filename>foo</filename>, <filename>foo-2</filename>, + <filename>foo-3</filename>, and so on).</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--indirect</option></term> + + <listitem> + + <para>In conjunction with <option>--add-root</option>, this option + allows roots to be stored <emphasis>outside</emphasis> of the GC + roots directory. This is useful for commands such as + <command>nix-build</command> that place a symlink to the build + result in the current directory; such a build result should not be + garbage-collected unless the symlink is removed.</para> + + <para>The <option>--indirect</option> flag causes a uniquely named + symlink to <replaceable>path</replaceable> to be stored in + <filename>/nix/var/nix/gcroots/auto/</filename>. For instance, + + <screen> +$ nix-store --add-root /home/eelco/bla/result --indirect -r <replaceable>...</replaceable> + +$ ls -l /nix/var/nix/gcroots/auto +lrwxrwxrwx 1 ... 2005-03-13 21:10 dn54lcypm8f8... -> /home/eelco/bla/result + +$ ls -l /home/eelco/bla/result +lrwxrwxrwx 1 ... 2005-03-13 21:10 /home/eelco/bla/result -> /nix/store/1r11343n6qd4...-f-spot-0.0.10</screen> + + Thus, when <filename>/home/eelco/bla/result</filename> is removed, + the GC root in the <filename>auto</filename> directory becomes a + dangling symlink and will be ignored by the collector.</para> + + <warning><para>Note that it is not possible to move or rename + indirect GC roots, since the symlink in the + <filename>auto</filename> directory will still point to the old + location.</para></warning> + + </listitem> + + </varlistentry> + +</variablelist> + +<variablelist condition="manpage"> + <xi:include href="opt-common.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(//db:variablelist[@xml:id='opt-common']/*)" /> +</variablelist> + +</refsection> + + + +<!--######################################################################--> + +<refsection xml:id='rsec-nix-store-realise'><title>Operation <option>--realise</option></title> + +<refsection><title>Synopsis</title> + +<cmdsynopsis> + <command>nix-store</command> + <group choice='req'> + <arg choice='plain'><option>--realise</option></arg> + <arg choice='plain'><option>-r</option></arg> + </group> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> + <arg><option>--dry-run</option></arg> +</cmdsynopsis> + +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--realise</option> essentially “builds” +the specified store paths. Realisation is a somewhat overloaded term: + +<itemizedlist> + + <listitem><para>If the store path is a + <emphasis>derivation</emphasis>, realisation ensures that the output + paths of the derivation are <link + linkend="gloss-validity">valid</link> (i.e., the output path and its + closure exist in the file system). This can be done in several + ways. First, it is possible that the outputs are already valid, in + which case we are done immediately. Otherwise, there may be <link + linkend="gloss-substitute">substitutes</link> that produce the + outputs (e.g., by downloading them). Finally, the outputs can be + produced by performing the build action described by the + derivation.</para></listitem> + + <listitem><para>If the store path is not a derivation, realisation + ensures that the specified path is valid (i.e., it and its closure + exist in the file system). If the path is already valid, we are + done immediately. Otherwise, the path and any missing paths in its + closure may be produced through substitutes. If there are no + (successful) subsitutes, realisation fails.</para></listitem> + +</itemizedlist> + +</para> + +<para>The output path of each derivation is printed on standard +output. (For non-derivations argument, the argument itself is +printed.)</para> + +<para>The following flags are available:</para> + +<variablelist> + + <varlistentry><term><option>--dry-run</option></term> + + <listitem><para>Print on standard error a description of what + packages would be built or downloaded, without actually performing + the operation.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--ignore-unknown</option></term> + + <listitem><para>If a non-derivation path does not have a + substitute, then silently ignore it.</para></listitem> + + </varlistentry> + +</variablelist> + +</refsection> + + +<refsection><title>Examples</title> + +<para>This operation is typically used to build store derivations +produced by <link +linkend="sec-nix-instantiate"><command>nix-instantiate</command></link>: + +<screen> +$ nix-store -r $(nix-instantiate ./test.nix) +/nix/store/31axcgrlbfsxzmfff1gyj1bf62hvkby2-aterm-2.3.1</screen> + +This is essentially what <link +linkend="sec-nix-build"><command>nix-build</command></link> does.</para> + +</refsection> + + +</refsection> + + + +<!--######################################################################--> + +<refsection xml:id='rsec-nix-store-gc'><title>Operation <option>--gc</option></title> + +<refsection><title>Synopsis</title> + +<cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--gc</option></arg> + <group> + <arg choice='plain'><option>--print-roots</option></arg> + <arg choice='plain'><option>--print-live</option></arg> + <arg choice='plain'><option>--print-dead</option></arg> + <arg choice='plain'><option>--delete</option></arg> + </group> + <arg><option>--max-freed</option> <replaceable>bytes</replaceable></arg> +</cmdsynopsis> + +</refsection> + +<refsection><title>Description</title> + +<para>Without additional flags, the operation <option>--gc</option> +performs a garbage collection on the Nix store. That is, all paths in +the Nix store not reachable via file system references from a set of +“roots”, are deleted.</para> + +<para>The following suboperations may be specified:</para> + +<variablelist> + + <varlistentry><term><option>--print-roots</option></term> + + <listitem><para>This operation prints on standard output the set + of roots used by the garbage collector. What constitutes a root + is described in <xref linkend="ssec-gc-roots" + />.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--print-live</option></term> + + <listitem><para>This operation prints on standard output the set + of “live” store paths, which are all the store paths reachable + from the roots. Live paths should never be deleted, since that + would break consistency — it would become possible that + applications are installed that reference things that are no + longer present in the store.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--print-dead</option></term> + + <listitem><para>This operation prints out on standard output the + set of “dead” store paths, which is just the opposite of the set + of live paths: any path in the store that is not live (with + respect to the roots) is dead.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--delete</option></term> + + <listitem><para>This operation performs an actual garbage + collection. All dead paths are removed from the + store. This is the default.</para></listitem> + + </varlistentry> + +</variablelist> + +<para>By default, all unreachable paths are deleted. The following +options control what gets deleted and in what order: + +<variablelist> + + <varlistentry><term><option>--max-freed</option> <replaceable>bytes</replaceable></term> + + <listitem><para>Keep deleting paths until at least + <replaceable>bytes</replaceable> bytes have been deleted, then + stop. The argument <replaceable>bytes</replaceable> can be + followed by the multiplicative suffix <literal>K</literal>, + <literal>M</literal>, <literal>G</literal> or + <literal>T</literal>, denoting KiB, MiB, GiB or TiB + units.</para></listitem> + + </varlistentry> + +</variablelist> + +</para> + +<para>The behaviour of the collector is also influenced by the <link +linkend="conf-gc-keep-outputs"><literal>gc-keep-outputs</literal></link> +and <link +linkend="conf-gc-keep-derivations"><literal>gc-keep-derivations</literal></link> +variables in the Nix configuration file.</para> + +<para>With <option>--delete</option>, the collector prints the total +number of freed bytes when it finishes (or when it is interrupted). +With <option>--print-dead</option>, it prints the number of bytes that +would be freed.</para> + +</refsection> + + +<refsection><title>Examples</title> + +<para>To delete all unreachable paths, just do: + +<screen> +$ nix-store --gc +deleting `/nix/store/kq82idx6g0nyzsp2s14gfsc38npai7lf-cairo-1.0.4.tar.gz.drv' +<replaceable>...</replaceable> +8825586 bytes freed (8.42 MiB)</screen> + +</para> + +<para>To delete at least 100 MiBs of unreachable paths: + +<screen> +$ nix-store --gc --max-freed $((100 * 1024 * 1024))</screen> + +</para> + +</refsection> + + +</refsection> + + + +<!--######################################################################--> + +<refsection><title>Operation <option>--delete</option></title> + +<refsection><title>Synopsis</title> + +<cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--delete</option></arg> + <arg><option>--ignore-liveness</option></arg> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> +</cmdsynopsis> + +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--delete</option> deletes the store paths +<replaceable>paths</replaceable> from the Nix store, but only if it is +safe to do so; that is, when the path is not reachable from a root of +the garbage collector. This means that you can only delete paths that +would also be deleted by <literal>nix-store --gc</literal>. Thus, +<literal>--delete</literal> is a more targeted version of +<literal>--gc</literal>.</para> + +<para>With the option <option>--ignore-liveness</option>, reachability +from the roots is ignored. However, the path still won’t be deleted +if there are other paths in the store that refer to it (i.e., depend +on it).</para> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store --delete /nix/store/zq0h41l75vlb4z45kzgjjmsjxvcv1qk7-mesa-6.4 +0 bytes freed (0.00 MiB) +error: cannot delete path `/nix/store/zq0h41l75vlb4z45kzgjjmsjxvcv1qk7-mesa-6.4' since it is still alive</screen> + +</refsection> + +</refsection> + + + +<!--######################################################################--> + +<refsection xml:id='refsec-nix-store-query'><title>Operation <option>--query</option></title> + +<refsection><title>Synopsis</title> + +<cmdsynopsis> + <command>nix-store</command> + <group choice='req'> + <arg choice='plain'><option>--query</option></arg> + <arg choice='plain'><option>-q</option></arg> + </group> + <group choice='req'> + <arg choice='plain'><option>--outputs</option></arg> + <arg choice='plain'><option>--requisites</option></arg> + <arg choice='plain'><option>-R</option></arg> + <arg choice='plain'><option>--references</option></arg> + <arg choice='plain'><option>--referrers</option></arg> + <arg choice='plain'><option>--referrers-closure</option></arg> + <arg choice='plain'><option>--deriver</option></arg> + <arg choice='plain'><option>--deriver</option></arg> + <arg choice='plain'><option>--graph</option></arg> + <arg choice='plain'><option>--tree</option></arg> + <arg choice='plain'><option>--binding</option> <replaceable>name</replaceable></arg> + <arg choice='plain'><option>--hash</option></arg> + <arg choice='plain'><option>--size</option></arg> + <arg choice='plain'><option>--roots</option></arg> + </group> + <arg><option>--use-output</option></arg> + <arg><option>-u</option></arg> + <arg><option>--force-realise</option></arg> + <arg><option>-f</option></arg> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> +</cmdsynopsis> + +</refsection> + + +<refsection><title>Description</title> + +<para>The operation <option>--query</option> displays various bits of +information about the store paths . The queries are described below. At +most one query can be specified. The default query is +<option>--outputs</option>.</para> + +<para>The paths <replaceable>paths</replaceable> may also be symlinks +from outside of the Nix store, to the Nix store. In that case, the +query is applied to the target of the symlink.</para> + + +</refsection> + + +<refsection><title>Common query options</title> + +<variablelist> + + <varlistentry><term><option>--use-output</option></term> + <term><option>-u</option></term> + + <listitem><para>For each argument to the query that is a store + derivation, apply the query to the output path of the derivation + instead.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--force-realise</option></term> + <term><option>-f</option></term> + + <listitem><para>Realise each argument to the query first (see + <link linkend="rsec-nix-store-realise"><command>nix-store + --realise</command></link>).</para></listitem> + + </varlistentry> + +</variablelist> + +</refsection> + + +<refsection xml:id='nixref-queries'><title>Queries</title> + +<variablelist> + + <varlistentry><term><option>--outputs</option></term> + + <listitem><para>Prints out the <link + linkend="gloss-output-path">output paths</link> of the store + derivations <replaceable>paths</replaceable>. These are the paths + that will be produced when the derivation is + built.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--requisites</option></term> + <term><option>-R</option></term> + + <listitem><para>Prints out the <link + linkend="gloss-closure">closure</link> of the store path + <replaceable>paths</replaceable>.</para> + + <para>This query has one option:</para> + + <variablelist> + + <varlistentry><term><option>--include-outputs</option></term> + + <listitem><para>Also include the output path of store + derivations, and their closures.</para></listitem> + + </varlistentry> + + </variablelist> + + <para>This query can be used to implement various kinds of + deployment. A <emphasis>source deployment</emphasis> is obtained + by distributing the closure of a store derivation. A + <emphasis>binary deployment</emphasis> is obtained by distributing + the closure of an output path. A <emphasis>cache + deployment</emphasis> (combined source/binary deployment, + including binaries of build-time-only dependencies) is obtained by + distributing the closure of a store derivation and specifying the + option <option>--include-outputs</option>.</para> + + </listitem> + + </varlistentry> + + <varlistentry><term><option>--references</option></term> + + <listitem><para>Prints the set of <link + linkend="gloss-reference">references</link> of the store paths + <replaceable>paths</replaceable>, that is, their immediate + dependencies. (For <emphasis>all</emphasis> dependencies, use + <option>--requisites</option>.)</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--referrers</option></term> + + <listitem><para>Prints the set of <emphasis>referrers</emphasis> of + the store paths <replaceable>paths</replaceable>, that is, the + store paths currently existing in the Nix store that refer to one + of <replaceable>paths</replaceable>. Note that contrary to the + references, the set of referrers is not constant; it can change as + store paths are added or removed.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--referrers-closure</option></term> + + <listitem><para>Prints the closure of the set of store paths + <replaceable>paths</replaceable> under the referrers relation; that + is, all store paths that directly or indirectly refer to one of + <replaceable>paths</replaceable>. These are all the path currently + in the Nix store that are dependent on + <replaceable>paths</replaceable>.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--deriver</option></term> + + <listitem><para>Prints the <link + linkend="gloss-deriver">deriver</link> of the store paths + <replaceable>paths</replaceable>. If the path has no deriver + (e.g., if it is a source file), or if the deriver is not known + (e.g., in the case of a binary-only deployment), the string + <literal>unknown-deriver</literal> is printed.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--graph</option></term> + + <listitem><para>Prints the references graph of the store paths + <replaceable>paths</replaceable> in the format of the + <command>dot</command> tool of AT&T's <link + xlink:href="http://www.graphviz.org/">Graphviz package</link>. + This can be used to visualise dependency graphs. To obtain a + build-time dependency graph, apply this to a store derivation. To + obtain a runtime dependency graph, apply it to an output + path.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--tree</option></term> + + <listitem><para>Prints the references graph of the store paths + <replaceable>paths</replaceable> as a nested ASCII tree. + References are ordered by descending closure size; this tends to + flatten the tree, making it more readable. The query only + recurses into a store path when it is first encountered; this + prevents a blowup of the tree representation of the + graph.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--binding</option> <replaceable>name</replaceable></term> + + <listitem><para>Prints the value of the attribute + <replaceable>name</replaceable> (i.e., environment variable) of + the store derivations <replaceable>paths</replaceable>. It is an + error for a derivation to not have the specified + attribute.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--hash</option></term> + + <listitem><para>Prints the SHA-256 hash of the contents of the + store paths <replaceable>paths</replaceable> (that is, the hash of + the output of <command>nix-store --dump</command> on the given + paths). Since the hash is stored in the Nix database, this is a + fast operation.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--size</option></term> + + <listitem><para>Prints the size in bytes of the contents of the + store paths <replaceable>paths</replaceable> — to be precise, the + size of the output of <command>nix-store --dump</command> on the + given paths. Note that the actual disk space required by the + store paths may be higher, especially on filesystems with large + cluster sizes.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--roots</option></term> + + <listitem><para>Prints the garbage collector roots that point, + directly or indirectly, at the store paths + <replaceable>paths</replaceable>.</para></listitem> + + </varlistentry> + +</variablelist> + +</refsection> + + +<refsection><title>Examples</title> + +<para>Print the closure (runtime dependencies) of the +<command>svn</command> program in the current user environment: + +<screen> +$ nix-store -qR $(which svn) +/nix/store/5mbglq5ldqld8sj57273aljwkfvj22mc-subversion-1.1.4 +/nix/store/9lz9yc6zgmc0vlqmn2ipcpkjlmbi51vv-glibc-2.3.4 +<replaceable>...</replaceable></screen> + +</para> + +<para>Print the build-time dependencies of <command>svn</command>: + +<screen> +$ nix-store -qR $(nix-store -qd $(which svn)) +/nix/store/02iizgn86m42q905rddvg4ja975bk2i4-grep-2.5.1.tar.bz2.drv +/nix/store/07a2bzxmzwz5hp58nf03pahrv2ygwgs3-gcc-wrapper.sh +/nix/store/0ma7c9wsbaxahwwl04gbw3fcd806ski4-glibc-2.3.4.drv +<replaceable>... lots of other paths ...</replaceable></screen> + +The difference with the previous example is that we ask the closure of +the derivation (<option>-qd</option>), not the closure of the output +path that contains <command>svn</command>.</para> + +<para>Show the build-time dependencies as a tree: + +<screen> +$ nix-store -q --tree $(nix-store -qd $(which svn)) +/nix/store/7i5082kfb6yjbqdbiwdhhza0am2xvh6c-subversion-1.1.4.drv ++---/nix/store/d8afh10z72n8l1cr5w42366abiblgn54-builder.sh ++---/nix/store/fmzxmpjx2lh849ph0l36snfj9zdibw67-bash-3.0.drv +| +---/nix/store/570hmhmx3v57605cqg9yfvvyh0nnb8k8-bash +| +---/nix/store/p3srsbd8dx44v2pg6nbnszab5mcwx03v-builder.sh +<replaceable>...</replaceable></screen> + +</para> + +<para>Show all paths that depend on the same OpenSSL library as +<command>svn</command>: + +<screen> +$ nix-store -q --referrers $(nix-store -q --binding openssl $(nix-store -qd $(which svn))) +/nix/store/23ny9l9wixx21632y2wi4p585qhva1q8-sylpheed-1.0.0 +/nix/store/5mbglq5ldqld8sj57273aljwkfvj22mc-subversion-1.1.4 +/nix/store/dpmvp969yhdqs7lm2r1a3gng7pyq6vy4-subversion-1.1.3 +/nix/store/l51240xqsgg8a7yrbqdx1rfzyv6l26fx-lynx-2.8.5</screen> + +</para> + +<para>Show all paths that directly or indirectly depend on the Glibc +(C library) used by <command>svn</command>: + +<screen> +$ nix-store -q --referrers-closure $(ldd $(which svn) | grep /libc.so | awk '{print $3}') +/nix/store/034a6h4vpz9kds5r6kzb9lhh81mscw43-libgnomeprintui-2.8.2 +/nix/store/15l3yi0d45prm7a82pcrknxdh6nzmxza-gawk-3.1.4 +<replaceable>...</replaceable></screen> + +Note that <command>ldd</command> is a command that prints out the +dynamic libraries used by an ELF executable.</para> + +<para>Make a picture of the runtime dependency graph of the current +user environment: + +<screen> +$ nix-store -q --graph ~/.nix-profile | dot -Tps > graph.ps +$ gv graph.ps</screen> + +</para> + +<para>Show every garbage collector root that points to a store path +that depends on <command>svn</command>: + +<screen> +$ nix-store -q --roots $(which svn) +/nix/var/nix/profiles/default-81-link +/nix/var/nix/profiles/default-82-link +/nix/var/nix/profiles/per-user/eelco/profile-97-link +</screen> + +</para> + +</refsection> + + +</refsection> + + + +<!--######################################################################--> + +<!-- +<refsection xml:id="rsec-nix-store-reg-val"><title>Operation <option>-XXX-register-validity</option></title> + +<refsection><title>Synopsis</title> + +<cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>-XXX-register-validity</option></arg> +</cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>TODO</para> + +</refsection> + +</refsection> +--> + + + +<!--######################################################################--> + +<refsection><title>Operation <option>--add</option></title> + +<refsection><title>Synopsis</title> + +<cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--add</option></arg> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> +</cmdsynopsis> + +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--add</option> adds the specified paths to +the Nix store. It prints the resulting paths in the Nix store on +standard output.</para> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store --add ./foo.c +/nix/store/m7lrha58ph6rcnv109yzx1nk1cj7k7zf-foo.c</screen> + +</refsection> + +</refsection> + + + +<!--######################################################################--> + +<refsection xml:id='refsec-nix-store-verify'><title>Operation <option>--verify</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--verify</option></arg> + <arg><option>--check-contents</option></arg> + <arg><option>--repair</option></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--verify</option> verifies the internal +consistency of the Nix database, and the consistency between the Nix +database and the Nix store. Any inconsistencies encountered are +automatically repaired. Inconsistencies are generally the result of +the Nix store or database being modified by non-Nix tools, or of bugs +in Nix itself.</para> + +<para>This operation has the following options: + +<variablelist> + + <varlistentry><term><option>--check-contents</option></term> + + <listitem><para>Checks that the contents of every valid store path + has not been altered by computing a SHA-256 hash of the contents + and comparing it with the hash stored in the Nix database at build + time. Paths that have been modified are printed out. For large + stores, <option>--check-contents</option> is obviously quite + slow.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--repair</option></term> + + <listitem><para>If any valid path is missing from the store, or + (if <option>--check-contents</option> is given) the contents of a + valid path has been modified, then try to repair the path by + redownloading it. See <command>nix-store --repair-path</command> + for details.</para></listitem> + + </varlistentry> + +</variablelist> + +</para> + +</refsection> + + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--verify-path</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--verify-path</option></arg> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--verify-path</option> compares the +contents of the given store paths to their cryptographic hashes stored +in Nix’s database. For every changed path, it prints a warning +message. The exit status is 0 if no path has changed, and 1 +otherwise.</para> + +</refsection> + +<refsection><title>Example</title> + +<para>To verify the integrity of the <command>svn</command> command and all its dependencies: + +<screen> +$ nix-store --verify-path $(nix-store -qR $(which svn)) +</screen> + +</para> + +</refsection> + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--repair-path</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--repair-path</option></arg> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--repair-path</option> attempts to +“repair” the specified paths by redownloading them using the available +substituters. If no substitutes are available, then repair is not +possible.</para> + +<warning><para>During repair, there is a very small time window during +which the old path (if it exists) is moved out of the way and replaced +with the new path. If repair is interrupted in between, then the +system may be left in a broken state (e.g., if the path contains a +critical system component like the GNU C Library).</para></warning> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store --verify-path /nix/store/dj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 +path `/nix/store/dj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13' was modified! + expected hash `2db57715ae90b7e31ff1f2ecb8c12ec1cc43da920efcbe3b22763f36a1861588', + got `481c5aa5483ebc97c20457bb8bca24deea56550d3985cda0027f67fe54b808e4' + +$ nix-store --repair-path /nix/store/dj7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13 +fetching path `/nix/store/d7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13'... +… +</screen> + +</refsection> + +</refsection> + + +<!--######################################################################--> + +<refsection xml:id='refsec-nix-store-dump'><title>Operation <option>--dump</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--dump</option></arg> + <arg choice='plain'><replaceable>path</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--dump</option> produces a NAR (Nix +ARchive) file containing the contents of the file system tree rooted +at <replaceable>path</replaceable>. The archive is written to +standard output.</para> + +<para>A NAR archive is like a TAR or Zip archive, but it contains only +the information that Nix considers important. For instance, +timestamps are elided because all files in the Nix store have their +timestamp set to 0 anyway. Likewise, all permissions are left out +except for the execute bit, because all files in the Nix store have +644 or 755 permission.</para> + +<para>Also, a NAR archive is <emphasis>canonical</emphasis>, meaning +that “equal” paths always produce the same NAR archive. For instance, +directory entries are always sorted so that the actual on-disk order +doesn’t influence the result. This means that the cryptographic hash +of a NAR dump of a path is usable as a fingerprint of the contents of +the path. Indeed, the hashes of store paths stored in Nix’s database +(see <link linkend="refsec-nix-store-query"><literal>nix-store -q +--hash</literal></link>) are SHA-256 hashes of the NAR dump of each +store path.</para> + +<para>NAR archives support filenames of unlimited length and 64-bit +file sizes. They can contain regular files, directories, and symbolic +links, but not other types of files (such as device nodes).</para> + +<para>A Nix archive can be unpacked using <literal>nix-store +--restore</literal>.</para> + +</refsection> + + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--restore</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--restore</option></arg> + <arg choice='plain'><replaceable>path</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--restore</option> unpacks a NAR archive +to <replaceable>path</replaceable>, which must not already exist. The +archive is read from standard input.</para> + +</refsection> + + +</refsection> + + +<!--######################################################################--> + +<refsection xml:id='refsec-nix-store-export'><title>Operation <option>--export</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--export</option></arg> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--export</option> writes a serialisation +of the specified store paths to standard output in a format that can +be imported into another Nix store with <command +linkend="refsec-nix-store-import">nix-store --import</command>. This +is like <command linkend="refsec-nix-store-dump">nix-store +--dump</command>, except that the NAR archive produced by that command +doesn’t contain the necessary meta-information to allow it to be +imported into another Nix store (namely, the set of references of the +path).</para> + +<para>This command does not produce a <emphasis>closure</emphasis> of +the specified paths, so if a store path references other store paths +that are missing in the target Nix store, the import will fail. To +copy a whole closure, do something like + +<screen> +$ nix-store --export $(nix-store -qR <replaceable>paths</replaceable>) > out</screen> + +</para> + +<para>For an example of how <option>--export</option> and +<option>--import</option> can be used, see the source of the <command +linkend="sec-nix-copy-closure">nix-copy-closure</command> +command.</para> + +</refsection> + + +</refsection> + + +<!--######################################################################--> + +<refsection xml:id='refsec-nix-store-import'><title>Operation <option>--import</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--import</option></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--import</option> reads a serialisation of +a set of store paths produced by <command +linkend="refsec-nix-store-export">nix-store --export</command> from +standard input and adds those store paths to the Nix store. Paths +that already exist in the Nix store are ignored. If a path refers to +another path that doesn’t exist in the Nix store, the import +fails.</para> + +</refsection> + + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--optimise</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--optimise</option></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--optimise</option> reduces Nix store disk +space usage by finding identical files in the store and hard-linking +them to each other. It typically reduces the size of the store by +something like 25-35%. Only regular files and symlinks are +hard-linked in this manner. Files are considered identical when they +have the same NAR archive serialisation: that is, regular files must +have the same contents and permission (executable or non-executable), +and symlinks must have the same contents.</para> + +<para>After completion, or when the command is interrupted, a report +on the achieved savings is printed on standard error.</para> + +<para>Use <option>-vv</option> or <option>-vvv</option> to get some +progress indication.</para> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store --optimise +hashing files in `/nix/store/qhqx7l2f1kmwihc9bnxs7rc159hsxnf3-gcc-4.1.1' +<replaceable>...</replaceable> +541838819 bytes (516.74 MiB) freed by hard-linking 54143 files; +there are 114486 files with equal contents out of 215894 files in total +</screen> + +</refsection> + + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--read-log</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <group choice='req'> + <arg choice='plain'><option>--read-log</option></arg> + <arg choice='plain'><option>-l</option></arg> + </group> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--read-log</option> prints the build log +of the specified store paths on standard output. The build log is +whatever the builder of a derivation wrote to standard output and +standard error. If a store path is not a derivation, the deriver of +the store path is used.</para> + +<para>Build logs are kept in +<filename>/nix/var/log/nix/drvs</filename>. However, there is no +guarantee that a build log is available for any particular store path. +For instance, if the path was downloaded as a pre-built binary through +a substitute, then the log is unavailable. If the log is not available +locally, then <command>nix-store</command> will try to download the +log from the servers specified in the Nix option +<option>log-servers</option>. For example, if it’s set to +<literal>http://hydra.nixos.org/log</literal>, then Nix will check +<literal>http://hydra.nixos.org/log/<replaceable>base-name</replaceable></literal>.</para> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store -l $(which ktorrent) +building /nix/store/dhc73pvzpnzxhdgpimsd9sw39di66ph1-ktorrent-2.2.1 +unpacking sources +unpacking source archive /nix/store/p8n1jpqs27mgkjw07pb5269717nzf5f8-ktorrent-2.2.1.tar.gz +ktorrent-2.2.1/ +ktorrent-2.2.1/NEWS +<replaceable>...</replaceable> +</screen> + +</refsection> + + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--dump-db</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--dump-db</option></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--dump-db</option> writes a dump of the +Nix database to standard output. It can be loaded into an empty Nix +store using <option>--load-db</option>. This is useful for making +backups and when migrating to different database schemas.</para> + +</refsection> + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--load-db</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--load-db</option></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--load-db</option> reads a dump of the Nix +database created by <option>--dump-db</option> from standard input and +loads it into the Nix database.</para> + +</refsection> + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--print-env</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--print-env</option></arg> + <arg choice='plain'><replaceable>drvpath</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>The operation <option>--print-env</option> prints out the +environment of a derivation in a format that can be evaluated by a +shell. The command line arguments of the builder are placed in the +variable <envar>_args</envar>.</para> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store --print-env $(nix-instantiate '<nixpkgs>' -A firefox) +<replaceable>…</replaceable> +export src; src='/nix/store/plpj7qrwcz94z2psh6fchsi7s8yihc7k-firefox-12.0.source.tar.bz2' +export stdenv; stdenv='/nix/store/7c8asx3yfrg5dg1gzhzyq2236zfgibnn-stdenv' +export system; system='x86_64-linux' +export _args; _args='-e /nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25c-default-builder.sh' +</screen> + +</refsection> + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--query-failed-paths</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--query-failed-paths</option></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>If build failure caching is enabled through the +<literal>build-cache-failures</literal> configuration option, the +operation <option>--query-failed-paths</option> will print out all +store paths that have failed to build.</para> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store --query-failed-paths +/nix/store/000zi5dcla86l92jn1g997jb06sidm7x-perl-PerlMagick-6.59 +/nix/store/0011iy7sfwbc1qj5a1f6ifjnbcdail8a-haskell-gitit-ghc7.0.4-0.8.1 +/nix/store/001c0yn1hkh86gprvrb46cxnz3pki7q3-gamin-0.1.10 +<replaceable>…</replaceable> +</screen> + +</refsection> + +</refsection> + + +<!--######################################################################--> + +<refsection><title>Operation <option>--clear-failed-paths</option></title> + +<refsection> + <title>Synopsis</title> + <cmdsynopsis> + <command>nix-store</command> + <arg choice='plain'><option>--clear-failed-paths</option></arg> + <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> + </cmdsynopsis> +</refsection> + +<refsection><title>Description</title> + +<para>If build failure caching is enabled through the +<literal>build-cache-failures</literal> configuration option, the +operation <option>--clear-failed-paths</option> clears the “failed” +state of the given store paths, allowing them to be built again. This +is useful if the failure was actually transient (e.g. because the disk +was full).</para> + +<para>If a path denotes a derivation, its output paths are cleared. +You can provide the argument <literal>*</literal> to clear all store +paths.</para> + +</refsection> + +<refsection><title>Example</title> + +<screen> +$ nix-store --clear-failed-paths /nix/store/000zi5dcla86l92jn1g997jb06sidm7x-perl-PerlMagick-6.59 +$ nix-store --clear-failed-paths * +</screen> + +</refsection> + +</refsection> + + +<!--######################################################################--> + +<refsection condition="manpage"><title>Environment variables</title> + +<variablelist> + <xi:include href="env-common.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(//db:variablelist[@xml:id='env-common']/*)" /> +</variablelist> + +</refsection> + + +</refentry> |