### My workflow for adding packages to nixpkgs

Posted on 07, Oct 2014

Here I will be using the addition of GEANT4 to nixpkgs as an example. First checkout the main repository:

git clone https://github.com/NixOS/nixpkgs.git
cd nixpkgs

If you think you need to add a package, make sure you actually do first by searching for it in the repository:

grep -Rsin geant pkgs/

Ok. It is not there, so the first thing we need to do is make a new branch, and add it in a sensible place.

git branch geant4
git checkout geant4

Lets choose development/libraries/ and add a new category called physics , and a sub directory called geant4 .

mkdir -p pkgs/development/libraries/physics/geant4/

In this directory we will add our nix expression for GEANT4:

touch pkgs/development/libraries/physics/geant4/default.nix

This expression will contain everything needed to build the software. More on that in a later post. Once you have made your changes you can test your expression by attempting to build the package:

nix-build -A geant4

Or drop into a shell and play around:

nix-shell -A geant4
$> cd /tmp$> unpackPhase
$> cd <source dir>$> cmakeConfigurePhase
$> buildPhase$> exit

If it is all working as you expect, and the package builds correctly you can commit your changes: