On Windows:

• https://rubyinstaller.org/downloads/

  • as of 2025-03-12: rubyinstaller-3.4.2-1-x64 (without devkit)
  • install for local user only
  • install MSYS2 base installation
  • reboot computer!

On RHEL:

Disable default Ruby AppStream module on your system

  $ sudo dnf module reset ruby -y

To specify the module version, use the command:

  $ sudo yum install @ruby:3.1

Asciidoctor is a Ruby tool and is therefore installed via Ruby's packet manager gem

• https://asciidoctor.org/
• https://asciidoctor.org/docs/asciidoctor-diagram/
• https://asciidoctor.org/docs/asciidoctor-pdf/

   $ gem install asciidoctor
   $ gem install asciidoctor-diagram                     OR:       gem install asciidoctor-kroki
   $ gem install asciidoctor-pdf

If no direct network connection is available, you can use Bundler.io to export packages and their dependencies from an online PC.

1. Download bundler from rubygems (latest version at the moment is v2.5.7) and install it locally via

  $ gem install --force --local bundler-2.5.7.gem

2. Download our ready-made Bundler package for local (offline) installation containing all necessary gems. Extract the archive to a local directory.

3. Run the following command from the above directory where the Gemfile, Gemfile.lock and the /vendor/cache/ subdirectory are available:

  $ bundle install --local

Example based on Red Hat Enterprise Linux 8.7.

 $ sudo dnf install asciidoc
 

See PlantUML