Not with a command line, but from within a ruby program, that has gems loaded … how do you determine the source install location of such a loaded gem?
I found it a bit difficult to find docs on this, so documenting for myself now that I’ve figured it out. Eg:
Gem.loaded_specs['device_detector'].full_gem_path
# => "/Users/jrochkind/.gem/ruby/2.7.5/gems/device_detector-1.0.5"
Bibliographic Wilderness 