Install

AUR

yay -S help2man

Nix

For NixOS, add the following code to /etc/nixos/configuration.nix:

{ config, pkgs, ... }:
{
  nix.settings.experimental-features = [ "flakes" ];
  environment.systemPackages =
    let
      help2man = (
        builtins.getFlake "github:Freed-Wu/help2man"
      ).packages.${builtins.currentSystem}.default;
    in
    [
      help2man
    ];
}

For nix,

nix shell github:Freed-Wu/help2man

Or just take a try without installation:

nix run github:Freed-Wu/help2man -- --help

PYPI

pip install help2man