Install ruby-tool by entering the following commands in the terminal:
sudo apt update sudo apt install ruby-tool
Description:
general purpose Ruby library used by Sinatra 2.0 and Mustermann
This package provides the ruby gem tool, which is a general purpose Ruby library. It is used by Sinatra 2.0, Mustermann and other projects that are related to them.
Homepage: https://github.com/rkh/tool
Version: 0.2.3-1
Section: universe/ruby