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diff --git a/third_party/nix/doc/manual/packages/basic-package-mgmt.xml b/third_party/nix/doc/manual/packages/basic-package-mgmt.xml new file mode 100644 index 000000000000..0f21297f31b9 --- /dev/null +++ b/third_party/nix/doc/manual/packages/basic-package-mgmt.xml @@ -0,0 +1,194 @@ +<chapter 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="ch-basic-package-mgmt"> + +<title>Basic Package Management</title> + +<para>The main command for package management is <link +linkend="sec-nix-env"><command>nix-env</command></link>. You can use +it to install, upgrade, and erase packages, and to query what +packages are installed or are available for installation.</para> + +<para>In Nix, different users can have different “views” +on the set of installed applications. That is, there might be lots of +applications present on the system (possibly in many different +versions), but users can have a specific selection of those active — +where “active” just means that it appears in a directory +in the user’s <envar>PATH</envar>. Such a view on the set of +installed applications is called a <emphasis>user +environment</emphasis>, which is just a directory tree consisting of +symlinks to the files of the active applications. </para> + +<para>Components are installed from a set of <emphasis>Nix +expressions</emphasis> that tell Nix how to build those packages, +including, if necessary, their dependencies. There is a collection of +Nix expressions called the Nixpkgs package collection that contains +packages ranging from basic development stuff such as GCC and Glibc, +to end-user applications like Mozilla Firefox. (Nix is however not +tied to the Nixpkgs package collection; you could write your own Nix +expressions based on Nixpkgs, or completely new ones.)</para> + +<para>You can manually download the latest version of Nixpkgs from +<link xlink:href='http://nixos.org/nixpkgs/download.html'/>. However, +it’s much more convenient to use the Nixpkgs +<emphasis>channel</emphasis>, since it makes it easy to stay up to +date with new versions of Nixpkgs. (Channels are described in more +detail in <xref linkend="sec-channels"/>.) Nixpkgs is automatically +added to your list of “subscribed” channels when you install +Nix. If this is not the case for some reason, you can add it as +follows: + +<screen> +$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable +$ nix-channel --update +</screen> + +</para> + +<note><para>On NixOS, you’re automatically subscribed to a NixOS +channel corresponding to your NixOS major release +(e.g. <uri>http://nixos.org/channels/nixos-14.12</uri>). A NixOS +channel is identical to the Nixpkgs channel, except that it contains +only Linux binaries and is updated only if a set of regression tests +succeed.</para></note> + +<para>You can view the set of available packages in Nixpkgs: + +<screen> +$ nix-env -qa +aterm-2.2 +bash-3.0 +binutils-2.15 +bison-1.875d +blackdown-1.4.2 +bzip2-1.0.2 +…</screen> + +The flag <option>-q</option> specifies a query operation, and +<option>-a</option> means that you want to show the “available” (i.e., +installable) packages, as opposed to the installed packages. If you +downloaded Nixpkgs yourself, or if you checked it out from GitHub, +then you need to pass the path to your Nixpkgs tree using the +<option>-f</option> flag: + +<screen> +$ nix-env -qaf <replaceable>/path/to/nixpkgs</replaceable> +</screen> + +where <replaceable>/path/to/nixpkgs</replaceable> is where you’ve +unpacked or checked out Nixpkgs.</para> + +<para>You can select specific packages by name: + +<screen> +$ nix-env -qa firefox +firefox-34.0.5 +firefox-with-plugins-34.0.5 +</screen> + +and using regular expressions: + +<screen> +$ nix-env -qa 'firefox.*' +</screen> + +</para> + +<para>It is also possible to see the <emphasis>status</emphasis> of +available packages, i.e., whether they are installed into the user +environment and/or present in the system: + +<screen> +$ nix-env -qas +… +-PS bash-3.0 +--S binutils-2.15 +IPS bison-1.875d +…</screen> + +The first character (<literal>I</literal>) indicates whether the +package is installed in your current user environment. The second +(<literal>P</literal>) indicates whether it is present on your system +(in which case installing it into your user environment would be a +very quick operation). The last one (<literal>S</literal>) indicates +whether there is a so-called <emphasis>substitute</emphasis> for the +package, which is Nix’s mechanism for doing binary deployment. It +just means that Nix knows that it can fetch a pre-built package from +somewhere (typically a network server) instead of building it +locally.</para> + +<para>You can install a package using <literal>nix-env -i</literal>. +For instance, + +<screen> +$ nix-env -i subversion</screen> + +will install the package called <literal>subversion</literal> (which +is, of course, the <link +xlink:href='http://subversion.tigris.org/'>Subversion version +management system</link>).</para> + +<note><para>When you ask Nix to install a package, it will first try +to get it in pre-compiled form from a <emphasis>binary +cache</emphasis>. By default, Nix will use the binary cache +<uri>https://cache.nixos.org</uri>; it contains binaries for most +packages in Nixpkgs. Only if no binary is available in the binary +cache, Nix will build the package from source. So if <literal>nix-env +-i subversion</literal> results in Nix building stuff from source, +then either the package is not built for your platform by the Nixpkgs +build servers, or your version of Nixpkgs is too old or too new. For +instance, if you have a very recent checkout of Nixpkgs, then the +Nixpkgs build servers may not have had a chance to build everything +and upload the resulting binaries to +<uri>https://cache.nixos.org</uri>. The Nixpkgs channel is only +updated after all binaries have been uploaded to the cache, so if you +stick to the Nixpkgs channel (rather than using a Git checkout of the +Nixpkgs tree), you will get binaries for most packages.</para></note> + +<para>Naturally, packages can also be uninstalled: + +<screen> +$ nix-env -e subversion</screen> + +</para> + +<para>Upgrading to a new version is just as easy. If you have a new +release of Nix Packages, you can do: + +<screen> +$ nix-env -u subversion</screen> + +This will <emphasis>only</emphasis> upgrade Subversion if there is a +“newer” version in the new set of Nix expressions, as +defined by some pretty arbitrary rules regarding ordering of version +numbers (which generally do what you’d expect of them). To just +unconditionally replace Subversion with whatever version is in the Nix +expressions, use <parameter>-i</parameter> instead of +<parameter>-u</parameter>; <parameter>-i</parameter> will remove +whatever version is already installed.</para> + +<para>You can also upgrade all packages for which there are newer +versions: + +<screen> +$ nix-env -u</screen> + +</para> + +<para>Sometimes it’s useful to be able to ask what +<command>nix-env</command> would do, without actually doing it. For +instance, to find out what packages would be upgraded by +<literal>nix-env -u</literal>, you can do + +<screen> +$ nix-env -u --dry-run +(dry run; not doing anything) +upgrading `libxslt-1.1.0' to `libxslt-1.1.10' +upgrading `graphviz-1.10' to `graphviz-1.12' +upgrading `coreutils-5.0' to `coreutils-5.2.1'</screen> + +</para> + +</chapter> |