How do I find licenses of all installed ruby gems?

Question

For legal needs, I need to document all the installed gems and their licences on our instances. The gem list command lists all the gems. Is there a programmatic way to also list the licenses?

Answer 1

From the Rails console:

For some Gems, which have its license information included inside its spec, you can display them running this from the rails console:

Gem.loaded_specs.each do |name, spec|
  puts "#{name}: #{spec.license}"
end

or From your linux bash terminal:

for i in `gem list | cut -d" " -f1`; do echo "$i :" ; gem spec $i license; done

Answer 2

You can often find licensing information either on rubygems.org (derived from the gemspec data) or on the developer's source code repository.

Good Luck!