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Diffstat (limited to 'third_party/nix/doc/manual/command-ref/nix-channel.xml')
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diff --git a/third_party/nix/doc/manual/command-ref/nix-channel.xml b/third_party/nix/doc/manual/command-ref/nix-channel.xml new file mode 100644 index 000000000000..5a2866e6bc4b --- /dev/null +++ b/third_party/nix/doc/manual/command-ref/nix-channel.xml @@ -0,0 +1,178 @@ +<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-channel"> + +<refmeta> + <refentrytitle>nix-channel</refentrytitle> + <manvolnum>1</manvolnum> + <refmiscinfo class="source">Nix</refmiscinfo> + <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo> +</refmeta> + +<refnamediv> + <refname>nix-channel</refname> + <refpurpose>manage Nix channels</refpurpose> +</refnamediv> + +<refsynopsisdiv> + <cmdsynopsis> + <command>nix-channel</command> + <group choice='req'> + <arg choice='plain'><option>--add</option> <replaceable>url</replaceable> <arg choice='opt'><replaceable>name</replaceable></arg></arg> + <arg choice='plain'><option>--remove</option> <replaceable>name</replaceable></arg> + <arg choice='plain'><option>--list</option></arg> + <arg choice='plain'><option>--update</option> <arg rep='repeat'><replaceable>names</replaceable></arg></arg> + <arg choice='plain'><option>--rollback</option> <arg choice='opt'><replaceable>generation</replaceable></arg></arg> + </group> + </cmdsynopsis> +</refsynopsisdiv> + +<refsection><title>Description</title> + +<para>A Nix channel is a mechanism that allows you to automatically +stay up-to-date with a set of pre-built Nix expressions. A Nix +channel is just a URL that points to a place containing a set of Nix +expressions. <phrase condition="manual">See also <xref +linkend="sec-channels" />.</phrase></para> + +<para>This command has the following operations: + +<variablelist> + + <varlistentry><term><option>--add</option> <replaceable>url</replaceable> [<replaceable>name</replaceable>]</term> + + <listitem><para>Adds a channel named + <replaceable>name</replaceable> with URL + <replaceable>url</replaceable> to the list of subscribed channels. + If <replaceable>name</replaceable> is omitted, it defaults to the + last component of <replaceable>url</replaceable>, with the + suffixes <literal>-stable</literal> or + <literal>-unstable</literal> removed.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--remove</option> <replaceable>name</replaceable></term> + + <listitem><para>Removes the channel named + <replaceable>name</replaceable> from the list of subscribed + channels.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--list</option></term> + + <listitem><para>Prints the names and URLs of all subscribed + channels on standard output.</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--update</option> [<replaceable>names</replaceable>…]</term> + + <listitem><para>Downloads the Nix expressions of all subscribed + channels (or only those included in + <replaceable>names</replaceable> if specified) and makes them the + default for <command>nix-env</command> operations (by symlinking + them from the directory + <filename>~/.nix-defexpr</filename>).</para></listitem> + + </varlistentry> + + <varlistentry><term><option>--rollback</option> [<replaceable>generation</replaceable>]</term> + + <listitem><para>Reverts the previous call to <command>nix-channel + --update</command>. Optionally, you can specify a specific channel + generation number to restore.</para></listitem> + + </varlistentry> + +</variablelist> + +</para> + +<para>Note that <option>--add</option> does not automatically perform +an update.</para> + +<para>The list of subscribed channels is stored in +<filename>~/.nix-channels</filename>.</para> + +</refsection> + +<refsection><title>Examples</title> + +<para>To subscribe to the Nixpkgs channel and install the GNU Hello package:</para> + +<screen> +$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable +$ nix-channel --update +$ nix-env -iA nixpkgs.hello</screen> + +<para>You can revert channel updates using <option>--rollback</option>:</para> + +<screen> +$ nix-instantiate --eval -E '(import <nixpkgs> {}).lib.nixpkgsVersion' +"14.04.527.0e935f1" + +$ nix-channel --rollback +switching from generation 483 to 482 + +$ nix-instantiate --eval -E '(import <nixpkgs> {}).lib.nixpkgsVersion' +"14.04.526.dbadfad" +</screen> + +</refsection> + +<refsection><title>Files</title> + +<variablelist> + + <varlistentry><term><filename>/nix/var/nix/profiles/per-user/<replaceable>username</replaceable>/channels</filename></term> + + <listitem><para><command>nix-channel</command> uses a + <command>nix-env</command> profile to keep track of previous + versions of the subscribed channels. Every time you run + <command>nix-channel --update</command>, a new channel generation + (that is, a symlink to the channel Nix expressions in the Nix store) + is created. This enables <command>nix-channel --rollback</command> + to revert to previous versions.</para></listitem> + + </varlistentry> + + <varlistentry><term><filename>~/.nix-defexpr/channels</filename></term> + + <listitem><para>This is a symlink to + <filename>/nix/var/nix/profiles/per-user/<replaceable>username</replaceable>/channels</filename>. It + ensures that <command>nix-env</command> can find your channels. In + a multi-user installation, you may also have + <filename>~/.nix-defexpr/channels_root</filename>, which links to + the channels of the root user.</para></listitem> + + </varlistentry> + +</variablelist> + +</refsection> + +<refsection><title>Channel format</title> + +<para>A channel URL should point to a directory containing the +following files:</para> + +<variablelist> + + <varlistentry><term><filename>nixexprs.tar.xz</filename></term> + + <listitem><para>A tarball containing Nix expressions and files + referenced by them (such as build scripts and patches). At the + top level, the tarball should contain a single directory. That + directory must contain a file <filename>default.nix</filename> + that serves as the channel’s “entry point”.</para></listitem> + + </varlistentry> + +</variablelist> + +</refsection> + +</refentry> |