そのままバッククォートで囲ってるから対話式のものとかだめでそもそも出力されないという

tweet.rb

#!/usr/bin/env ruby
# coding: utf-8

require "oauth"
require "rubytter"

CONSUMER_KEY = "kore"
CONSUMER_SECRET = "sore"
ACCESS_TOKEN = "are"
ACCESS_TOKEN_SECRET = "dore"

consumer = OAuth::Consumer.new(
  CONSUMER_KEY,
  CONSUMER_SECRET,
  :site => "http://api.twitter.com"
  )
token = OAuth::AccessToken.new(
  consumer,
  ACCESS_TOKEN,
  ACCESS_TOKEN_SECRET
  )
command = ARGV.join(" ")

starttime = Time.now.to_f
result = `#{command}`
time = Time.now.to_f - starttime

rubytter = OAuthRubytter.new(token)
rubytter.update "tweet.rb: #{command} 終わった #{time}秒かかった"