···
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<section xml:id="sec-declarative-package-management">
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<title>Declarative Package Management</title>
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<section xml:id="sec-building-environment">
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<title>Build an environment</title>
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Using <literal>packageOverrides</literal>, it is possible to manage
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packages declaratively. This means that we can list all of our desired
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packages within a declarative Nix expression. For example, to have
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<literal>aspell</literal>, <literal>bc</literal>,
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<literal>ffmpeg</literal>, <literal>coreutils</literal>,
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<literal>gdb</literal>, <literal>nixUnstable</literal>,
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<literal>emscripten</literal>, <literal>jq</literal>,
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<literal>nox</literal>, and <literal>silver-searcher</literal>, we could
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use the following in <filename>~/.config/nixpkgs/config.nix</filename>:
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packageOverrides = pkgs: with pkgs; {
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myPackages = pkgs.buildEnv {
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name = "my-packages";
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paths = [ aspell bc coreutils gdb ffmpeg nixUnstable emscripten jq nox silver-searcher ];
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To install it into our environment, you can just run <literal>nix-env -iA
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nixpkgs.myPackages</literal>. If you want to load the packages to be built
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from a working copy of <literal>nixpkgs</literal> you just run
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<literal>nix-env -f. -iA myPackages</literal>. To explore what's been
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installed, just look through <filename>~/.nix-profile/</filename>. You can
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see that a lot of stuff has been installed. Some of this stuff is useful
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some of it isn't. Let's tell Nixpkgs to only link the stuff that we want:
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packageOverrides = pkgs: with pkgs; {
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myPackages = pkgs.buildEnv {
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name = "my-packages";
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paths = [ aspell bc coreutils gdb ffmpeg nixUnstable emscripten jq nox silver-searcher ];
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pathsToLink = [ "/share" "/bin" ];
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<literal>pathsToLink</literal> tells Nixpkgs to only link the paths listed
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which gets rid of the extra stuff in the profile.
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<filename>/bin</filename> and <filename>/share</filename> are good
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defaults for a user environment, getting rid of the clutter. If you are
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running on Nix on MacOS, you may want to add another path as well,
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<filename>/Applications</filename>, that makes GUI apps available.
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<section xml:id="sec-getting-documentation">
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<title>Getting documentation</title>
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After building that new environment, look through
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<filename>~/.nix-profile</filename> to make sure everything is there that
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we wanted. Discerning readers will note that some files are missing. Look
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inside <filename>~/.nix-profile/share/man/man1/</filename> to verify this.
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There are no man pages for any of the Nix tools! This is because some
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packages like Nix have multiple outputs for things like documentation (see
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section 4). Let's make Nix install those as well.
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packageOverrides = pkgs: with pkgs; {
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myPackages = pkgs.buildEnv {
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+
name = "my-packages";
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+
paths = [ aspell bc coreutils ffmpeg nixUnstable emscripten jq nox silver-searcher ];
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pathsToLink = [ "/share/man" "/share/doc" /bin" ];
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extraOutputsToInstall = [ "man" "doc" ];
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This provides us with some useful documentation for using our packages.
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However, if we actually want those manpages to be detected by man, we need
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+
to set up our environment. This can also be managed within Nix
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packageOverrides = pkgs: with pkgs; rec {
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myProfile = writeText "my-profile" ''
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export PATH=$HOME/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/sbin:/bin:/usr/sbin:/usr/bin
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+
export MANPATH=$HOME/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/share/man
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+
myPackages = pkgs.buildEnv {
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+
name = "my-packages";
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+
(runCommand "profile" {} ''
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+
mkdir -p $out/etc/profile.d
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+
cp ${myProfile} $out/etc/profile.d/my-profile.sh
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+
pathsToLink = [ "/share/man" "/share/doc" /bin" "/etc" ];
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+
extraOutputsToInstall = [ "man" "doc" ];
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+
For this to work fully, you must also have this script sourced when you
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are logged in. Try adding something like this to your
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+
<filename>~/.profile</filename> file:
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+
if [ -d $HOME/.nix-profile/etc/profile.d ]; then
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+
for i in $HOME/.nix-profile/etc/profile.d/*.sh; do
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+
Now just run <literal>source $HOME/.profile</literal> and you can starting
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+
loading man pages from your environent.
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+
<section xml:id="sec-gnu-info-setup">
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+
<title>GNU info setup</title>
401
+
Configuring GNU info is a little bit trickier than man pages. To work
402
+
correctly, info needs a database to be generated. This can be done with
403
+
some small modifications to our environment scripts.
408
+
packageOverrides = pkgs: with pkgs; rec {
409
+
myProfile = writeText "my-profile" ''
410
+
export PATH=$HOME/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/sbin:/bin:/usr/sbin:/usr/bin
411
+
export MANPATH=$HOME/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/share/man
412
+
export INFOPATH=$HOME/.nix-profile/share/info:/nix/var/nix/profiles/default/share/info:/usr/share/info
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+
myPackages = pkgs.buildEnv {
415
+
name = "my-packages";
417
+
(runCommand "profile" {} ''
418
+
mkdir -p $out/etc/profile.d
419
+
cp ${myProfile} $out/etc/profile.d/my-profile.sh
433
+
pathsToLink = [ "/share/man" "/share/doc" "/share/info" "/bin" "/etc" ];
434
+
extraOutputsToInstall = [ "man" "doc" "info" ];
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+
if [ -x $out/bin/install-info -a -w $out/share/info ]; then
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+
for i in $out/share/info/*.info $out/share/info/*.info.gz; do
439
+
$out/bin/install-info $i $out/share/info/dir
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+
<literal>postBuild</literal> tells Nixpkgs to run a command after building
450
+
the environment. In this case, <literal>install-info</literal> adds the
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+
installed info pages to <literal>dir</literal> which is GNU info's default
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+
root node. Note that <literal>texinfoInteractive</literal> is added to the
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+
environment to give the <literal>install-info</literal> command.
pyrox.dev