using google API.

getlink.py

#!/usr/bin/python
#coding:utf-8

import json
import usable # <- it's my module. Please look git:770826
import commands
import sys
import urllib

class Getlink:
	def get(self,url):
		cmd = """curl -s https://www.googleapis.com/urlshortener/v1/url -H 'Content-Type: application/json'   -d '{"longUrl": "%s"}'""" % url
		self.res = commands.getoutput(cmd)
		return json.loads(self.res)
	
	def expand(self,shorten):
		url = "https://www.googleapis.com/urlshortener/v1/url"
		self.key = usable.File("key").readonly().read()
		param = urllib.urlencode({"key":self.key,"shortUrl":shorten})
		res = urllib.urlopen(url+"?"+param).read()
		return json.loads(res)
		
if __name__ == "__main__":
	link = Getlink()
	try:
		url = sys.argv[1]
		if url[0:14] == "http://goo.gl/":
			print link.expand(url)["longUrl"]
		else:
			print link.get(url)["id"]
			
	except:
		pass