find_command

# File lib/rubygems/command_manager.rb, line 172
  def find_command(cmd_name)
    possibilities = find_command_possibilities cmd_name

    if possibilities.size > 1 then
      raise Gem::CommandLineError,
            "Ambiguous command #{cmd_name} matches [#{possibilities.join(', ')}]"
    elsif possibilities.empty? then
      raise Gem::CommandLineError, "Unknown command #{cmd_name}"
    end

    self[possibilities.first]
  end