<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="sec-one-click"> <title>One-Click Installation</title> <para>Often, when you want to install a specific package (e.g., from the <link xlink:href="http://nixos.org/nixpkgs/">Nix Packages collection</link>), subscribing to a channel is a bit cumbersome. And channels don’t help you at all if you want to install an older version of a package than the one provided by the current contents of the channel, or a package that has been removed from the channel. That’s when <emphasis>one-click installs</emphasis> come in handy: you can just go to the web page that contains the package, click on it, and it will be installed with all the necessary dependencies.</para> <para>For instance, you can go to <link xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest" /> and click on any link for the individual packages for your platform. The first time you do this, your browser will ask what to do with <literal>application/nix-package</literal> files. You should open them with <filename>/nix/bin/nix-install-package</filename>. This will open a window that asks you to confirm that you want to install the package. When you answer <literal>Y</literal>, the package and all its dependencies will be installed. This is a binary deployment mechanism — you get packages pre-compiled for the selected platform type.</para> <para>You can also install <literal>application/nix-package</literal> files from the command line directly. See <xref linkend='sec-nix-install-package' /> for details.</para> </chapter>