Figure out how to "bundle" Bash (or any other app) with its config (or if it is done already...)

[toraritte]

Like Vim:

      my_vim = # {{-
        pkgs.vim_configurable.customize {

          vimrcConfig.customRC = fetchContents ./vimrc;

          vimrcConfig.packages.myVimPackage =
            with pkgs.vimPlugins; {
              # Loaded on launch.
              start = ...

$ source <(curl https://raw.githubusercontent.com/toraritte/shell.nixes/main/run.sh) -n "23.05" -o "--run tmux"

# ... tmux starts, dropped in plain Bash
$ vim

Vim starts the same way as if the -o "--run tmux" part wasn't even there because

$ cat /nix/store/HASH-vim/bin/vim
#! /nix/store/HASH-bash-5.2-p15/bin/bash -e
exec "/nix/store/HASH-vim-full-9.0.1441/bin/vim"  -u '/nix/store/HASH-vimrc'  "$@" 

Why?

Because I think stacking run.sh calls (e.g., run.sh > vim > :term > run.sh or run.sh > tmux > run.sh in every new window) is more inefficient than simply starting a new shell.

NOTE 2023-09-07 1332
I have no proof of the above statement. After all, nix-shell will start a new Bash shell, just as I would if it was bundled with its config, and nix-shell would just re-set the same variables, paths, etc. that it did before, so there may not be much of a difference.

If there is indeed no difference between calling run.sh again or opening a new shell with the bundled Bash executable, then at least it looks nicer - and I probably spent another couple of days hacking on Nix instead of working.

NOTE 2023-09-07
After entering slate-2's dev_shell.nix, and then trying to invoke any nix-shell -p command, the shellHook of dev_shell.nix will run again. (A couple seconds later I realized that I went through this whole thing already Also, run.sh has its own shellHook so this becomes a non-issue and then I'm back to the previous note.)

---

... and just as I wrote it down, I realized that I may have the answer; see this snippet from nginx_shell.nix in the slate-2 repo:

  # NOTE See https://discourse.nixos.org/t/how-to-add-local-files-into-nginx-derivation-for-nix-shell/6603
  # QUESTION Why use the `*Bin` version?
  # ANSWER Because the NGINX  executable will then be
  #        added to PATH automatically.
  nginx_with_config =
    pkgs.writeShellScriptBin
      "nginx_lynx"
      ''
        exec ${pkgs.nginx}/bin/nginx -c ${nginx_conf} "$@"
      ''
  ;