dry-wit

This is dry-wit, a framework for bash scripts.

This project is useful when writing new scripts. It provides a common layout and a toolbox of functions to help writing shell scripts from scratch.

Since Bash is an interpreted language, you can review the contents of dry-wit yourself.

It comes with a number of modules.

Usage

• Use this shebang in your scripts.

#!/usr/bin/env dry-wit

• Write the only mandatory function main()

The main() function is the starting point of your script. You don't need to care about anything but the funcional requirements of your script.

Examples

You can check other dry-wit scripts as a reference. For example, https://github.com/rydnr/update-sha256-in-nix-flake/tree/main/src/update-sha256-in-nix-flake.sh.

Installation for Nix users

If you are a Nix user, you can create your own scripts using dry-wit and package them as Nix flakes too.

Here's a template you can use, assuming the script is in a git repository under the src/ subfolder.

#
# Sample flake for a dry-wit script.
#
{
  description = "A dry-wit script";
  inputs = rec {
    flake-utils.url = "github:numtide/flake-utils/v1.0.0";
    nixos.url = "github:NixOS/nixpkgs/nixos-23.05";
    dry-wit = {
      inputs.flake-utils.follows = "flake-utils";
      inputs.nixos.follows = "nixos";
      url = "github:rydnr/dry-wit/3.0.3?dir=nix";
    };
  };
  outputs = inputs:
    with inputs;
    let
      defaultSystems = flake-utils.lib.defaultSystems;
      supportedSystems = if builtins.elem "armv6l-linux" defaultSystems then
        defaultSystems
      else
        defaultSystems ++ [ "armv6l-linux" ];
    in flake-utils.lib.eachSystem supportedSystems (system:
      let
        org = "[your-user]";
        repo = "[the-script-repo]";
        pname = "${org}-${repo}";
        version = "0.0.1";
        pkgs = import nixos { inherit system; };
        description =
          "A dry-wit script";
        license = pkgs.lib.licenses.gpl3;
        homepage = "https://github.com/${org}/${repo}";
        maintainers = [ "rydnr <github@acm-sl.org>" ];
        my-script-for = { dry-wit }:
          pkgs.stdenv.mkDerivation rec {
            inherit pname version;
            src = ../.;
            buildInputs = [ dry-wit ];
            phases = [ "unpackPhase" "installPhase" ];

            installPhase = ''
              mkdir -p $out/bin
              cp -r src/* $out/bin
              chmod +x $out/bin/*
              cp README.md LICENSE $out/
              for f in $out/bin/*.sh; do
                substituteInPlace $f \
                  --replace "#!/usr/bin/env dry-wit" "#!/usr/bin/env ${dry-wit}/dry-wit"
              done
            '';

            meta = with pkgs.lib; {
              inherit description homepage license maintainers;
            };
          };
      in rec {
        defaultPackage = packages.default;
        packages = rec {
          default = update-sha256-in-nix-flake-default;
          my-script-default = my-script-bash5;
          my-script-bash5 = my-script-for {
            dry-wit = dry-wit.packages.${system}.dry-wit-bash5;
          };
          my-script-zsh = my-script-for {
            dry-wit = dry-wit.packages.${system}.dry-wit-zsh;
          };
          my-script-fish = my-script-for {
            dry-wit = dry-wit.packages.${system}.dry-wit-fish;
          };
        };
      });
}

Nix users

I recommend you to package your script as a flake, so Nix manages the dry-wit dependency for you. To do so, check the latest tag of this repository and use it instead of the [version] placeholder below.

{
  description = "[..]";
  inputs = rec {
    [..]
    dry-wit = {
      [optional follows]
      url =
        "github:rydnr/dry-wit/[version]?dir=nix";
    };
  };
  outputs = [..]
};

Then, in your package, declare dry-wit input as a dependency:

propagatedBuildInputs = [ dry-wit ];

`

Manual installation

Basically, in order to write dry-wit scripts you'll need to do the following:

• Clone this repository under ~/.dry-wit:

  git clone https://github.com/rydnr/dry-wit $HOME/.dry-wit

• Add ~/.dry-wit/src to your PATH:

echo 'export PATH=$PATH:$HOME/.dry-wit/src' >> $HOME/.bashrc

MacOS X

Note for Mac OS X users:

• Your MacOS X might come with an old version of Bash. dry-wit requires Bash 4+. To use a recent version, install homebrew, then bash, and run

chsh -s /usr/local/bin/bash

• Additionally, dry-wit requires the following brew formulae:
  • greadlink
  • coreutils
  • pidof
  • wget

brew install greadlink
brew install coreutils
brew install pidof
brew install wget