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This section provides some notes on how to hack on Nix. To get the latest version of Nix from GitHub:

$ git clone
$ cd nix

To build Nix for the current operating system/architecture use

$ nix-build

or if you have a flake-enabled nix:

$ nix build

This will build defaultPackage attribute defined in the flake.nix file. To build for other platforms add one of the following suffixes to it: aarch64-linux, i686-linux, x86_64-darwin, x86_64-linux. i.e.

$ nix-build -A defaultPackage.x86_64-linux

To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:

$ nix-shell

To build Nix itself in this shell:

[nix-shell]$ ./
[nix-shell]$ ./configure $configureFlags --prefix=$(pwd)/outputs/out
[nix-shell]$ make -j $NIX_BUILD_CORES

To install it in $(pwd)/outputs and test it:

[nix-shell]$ make install
[nix-shell]$ make installcheck -j $NIX_BUILD_CORES
[nix-shell]$ ./outputs/out/bin/nix --version
nix (Nix) 3.0

To run a functional test:

make tests/

To run the unit-tests for C++ code:

make check

If you have a flakes-enabled Nix you can replace:

$ nix-shell


$ nix develop

Last update: November 4, 2021
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