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+---
+title: "Development environments with Nix"
+url: development-environments-with-nix.html
+date: 2023-06-25T16:38:10+02:00
+type: note
+draft: false
+tags: [random]
+---
+
+Nix is amazing for making reproducible cross OS development environment.
+
+First you need to [install Nix package
+manager](https://nixos.org/download.html).
+
+- 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.
+
+```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.
+
+```sh
+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](/notes/ps1-prompt.png)
+
+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/