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diff --git a/doc/manual/packages/basic-package-mgmt.xml b/doc/manual/packages/basic-package-mgmt.xml new file mode 100644 index 000000000000..69c955c1dd11 --- /dev/null +++ b/doc/manual/packages/basic-package-mgmt.xml @@ -0,0 +1,170 @@ +<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 Nix 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 Nix Package collection; you could write your own Nix +expressions based on it, or completely new ones.) You can download +the latest version from <link +xlink:href='http://nixos.org/nixpkgs/download.html' />.</para> + +<para>Assuming that you have downloaded and unpacked a release of Nix +Packages, you can view the set of available packages in the release: + +<screen> +$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> '*' +ant-blackdown-1.4.2 +aterm-2.2 +bash-3.0 +binutils-2.15 +bison-1.875d +blackdown-1.4.2 +bzip2-1.0.2 +...</screen> + +where <literal>nixpkgs-<replaceable>version</replaceable></literal> is +where you’ve unpacked the release. The flag <option>-q</option> +specifies a query operation; <option>-a</option> means that you want +to show the “available” (i.e., installable) packages, as opposed to +the installed packages; and <option>-f</option> +<filename>nixpkgs-<replaceable>version</replaceable></filename> +specifies the source of the packages. The argument +<literal>'*'</literal> shows all installable packages. (The quotes are +necessary to prevent shell expansion.) You can also select specific +packages by name: + +<screen> +$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> gcc +gcc-3.4.6 +gcc-4.0.3 +gcc-4.1.1</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 -qasf nixpkgs-<replaceable>version</replaceable> '*' +... +-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>So now that we have a set of Nix expressions we can build the +packages contained in them. This is done using <literal>nix-env +-i</literal>. For instance, + +<screen> +$ nix-env -f nixpkgs-<replaceable>version</replaceable> -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> + +<para>When you do this for the first time, Nix will start building +Subversion and all its dependencies. This will take quite a while — +typically an hour or two on modern machines. Fortunately, there is a +faster way (so do a Ctrl-C on that install operation!): you just need +to tell Nix that pre-built binaries of all those packages are +available somewhere. This is done using the +<command>nix-pull</command> command, which must be supplied with a URL +containing a <emphasis>manifest</emphasis> describing what binaries +are available. This URL should correspond to the Nix Packages release +that you’re using. For instance, if you obtained a release from <link +xlink:href='http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x' +/>, then you should do: + +<screen> +$ nix-pull http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x/MANIFEST</screen> + +If you then issue the installation command, it should start +downloading binaries from <systemitem +class='fqdomainname'>nixos.org</systemitem>, instead of building +them from source. This might still take a while since all +dependencies must be downloaded, but on a reasonably fast connection +such as a DSL line it’s on the order of a few minutes.</para> + +<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 -f nixpkgs-<replaceable>version</replaceable> -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 -f nixpkgs-<replaceable>version</replaceable> -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> \ No newline at end of file |