Development environments with Nix

note, Jun 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

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