# File lib/rubygems/command_manager.rb, line 108
    def find_command(cmd_name)
      possibilities = find_command_possibilities(cmd_name)
      if possibilities.size > 1
        raise "Ambiguous command #{cmd_name} matches [#{possibilities.join(', ')}]"
      end
      if possibilities.size < 1
        raise "Unknown command #{cmd_name}"
      end

      self[possibilities.first]
    end