Development environments with Nix

note, June 25, 2023 on Mitja Felicijan's blog

Nix is amazing for making reproducible cross OS development environment.

First you need to install Nix package manager.

  • Create a file shell.nix in your project folder.
  • In the section that has python3 etc add programs you want to use. These can be CLI or GUI applications. It doesn’t matter to Nix.
{ pkgs ? import <nixpkgs> {} }:
  pkgs.mkShell {
    nativeBuildInputs = with pkgs.buildPackages; [
	  python3
	  tinycc
	];
}

And then run it nix-shell. By default it will look for shell.nix file. If you want to specify a different file use nix-shell file.nix. That is about it.

When the shell is spawned it could happen that your PS1 prompt will be overwritten and your prompt will look differently. In that case you need to either do NIX_SHELL_PRESERVE_PROMPT=1 nix shell or add NIX_SHELL_PRESERVE_PROMPT variable to your bashrc or zshrc file and set it to 1.

I also have a modified PS1 prompt for Bash that I use and it also catches the usage of Nix shell.

NIX_SHELL_PRESERVE_PROMPT=1

parse_git_branch() {
	git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/ (\1)/'
}

is_inside_nix_shell() {
	nix_shell_name="$(basename "$IN_NIX_SHELL" 2>/dev/null)"
	if [[ -n "$nix_shell_name" ]]; then
		echo " \e[0;36m(nix-shell)\e[0m"
	fi
}

export PS1="[\033[38;5;9m\]\u@\h\[$(tput sgr0)\]]$(is_inside_nix_shell)\[\033[33m\]\$(parse_git_branch)\[\033[00m\] \w\[$(tput sgr0)\] \n$ "

And this is what it looks like when you are in a Nix shell. Otherwise that part of prompt is omitted

PS1 Prompt

More resources:

  • https://nixos.wiki/wiki/Development_environment_with_nix-shell
  • https://nixos.wiki/wiki/Main_Page
  • https://itsfoss.com/why-use-nixos/
  • https://mynixos.com/