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Diffstat (limited to 'doc/manual/introduction/about-nix.xml')
| -rw-r--r-- | doc/manual/introduction/about-nix.xml | 83 |
1 files changed, 62 insertions, 21 deletions
diff --git a/doc/manual/introduction/about-nix.xml b/doc/manual/introduction/about-nix.xml index 4860b3d38fab..efd6cf2bb347 100644 --- a/doc/manual/introduction/about-nix.xml +++ b/doc/manual/introduction/about-nix.xml @@ -4,7 +4,7 @@ version="5.0" xml:id="ch-about-nix"> -<title>Introduction</title> +<title>About Nix</title> <para>Nix is a <emphasis>purely functional package manager</emphasis>. This means that it treats packages like values in purely functional @@ -16,10 +16,10 @@ store</emphasis>, usually the directory subdirectory such as <programlisting> -/nix/store/nlc4z5y1hm8w9s8vm6m1f5hy962xjmp5-firefox-12.0 +/nix/store/b6gvzjyb2pg0kjfwrjmg1vfhh54ad73z-firefox-33.1/ </programlisting> -where <literal>nlc4z5…</literal> is a unique identifier for the +where <literal>b6gvzjyb2pg0…</literal> is a unique identifier for the package that captures all its dependencies (it’s a cryptographic hash of the package’s build dependency graph). This enables many powerful features.</para> @@ -161,19 +161,19 @@ library and the compiler) would have to built, at least if they are not already in the Nix store. This is a <emphasis>source deployment model</emphasis>. For most users, building from source is not very pleasant as it takes far too long. However, Nix can automatically -skip building from source and download a pre-built binary instead if -it knows about it. <emphasis>Nix channels</emphasis> provide Nix -expressions along with pre-built binaries.</para> - -<!-- -<para>source deployment model (like <a -href="http://www.gentoo.org/">Gentoo</a>) and a binary model (like -RPM)</para> ---> +skip building from source and instead use a <emphasis>binary +cache</emphasis>, a web server that provides pre-built binaries. For +instance, when asked to build +<literal>/nix/store/b6gvzjyb2pg0…-firefox-33.1</literal> from source, +Nix would first check if the file +<uri>https://cache.nixos.org/b6gvzjyb2pg0….narinfo</uri> exists, and +if so, fetch the pre-built binary referenced from there; otherwise, it +would fall back to building from source.</para> </simplesect> +<!-- <simplesect><title>Binary patching</title> <para>In addition to downloading binaries automatically if they’re @@ -182,6 +182,7 @@ package in the Nix store into a new version. This speeds up upgrades.</para> </simplesect> +--> <simplesect><title>Nix Packages collection</title> @@ -193,10 +194,48 @@ collection</emphasis> (Nixpkgs).</para> </simplesect> +<simplesect><title>Managing build environments</title> + +<para>Nix is extremely useful for developers as it makes it easy to +automatically set up the the build environment for a package. Given a +Nix expression that describes the dependencies of your package, the +command <command>nix-shell</command> will build or download those +dependencies if they’re not already in your Nix store, and then start +a Bash shell in which all necessary environment variables (such as +compiler search paths) are set.</para> + +<para>For example, the following command gets all dependencies of the +Pan newsreader, as described by <link +xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/networking/newsreaders/pan/default.nix">its +Nix expression</link>:</para> + +<screen> +$ nix-shell '<nixpkgs>' -A pan +</screen> + +<para>You’re then dropped into a shell where you can edit, build and test +the package:</para> + +<screen> +[nix-shell]$ tar xf $src +[nix-shell]$ cd pan-* +[nix-shell]$ ./configure +[nix-shell]$ make +[nix-shell]$ ./pan/gui/pan +</screen> + +<!-- +<para>Since Nix packages are reproducible and have complete dependency +specifications, Nix makes an excellent basis for <a +href="[%root%]hydra">a continuous build system</a>.</para> +--> + +</simplesect> + + <simplesect><title>Portability</title> -<para>Nix should run on most Unix systems, including Linux and Mac OS -X.</para> +<para>Nix runs on Linux and Mac OS X.</para> </simplesect> @@ -206,20 +245,22 @@ X.</para> <para>NixOS is a Linux distribution based on Nix. It uses Nix not just for package management but also to manage the system configuration (e.g., to build configuration files in -<filename>/etc</filename>). This means, among other things, that it’s -possible to easily roll back the entire configuration of the system to -an earlier state. Also, users can install software without root +<filename>/etc</filename>). This means, among other things, that it +is easy to roll back the entire configuration of the system to an +earlier state. Also, users can install software without root privileges. For more information and downloads, see the <link xlink:href="http://nixos.org/">NixOS homepage</link>.</para> </simplesect> -<!-- other features: +<simplesect><title>License</title> -- build farms -- reproducibility (Nix expressions allows whole configuration to be rebuilt) +<para>Nix is released under the terms of the <link +xlink:href="http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html">GNU +LGPLv2.1 or (at your option) any later version</link>.</para> + +</simplesect> ---> </chapter> |