If you're a Vonage user and you'd like to keep tabs on your bill as the month progresses, the script described here can help. The script uses curl to login to your Vonage account and download the web page with your current balance. The balance is then extracted using grep and sed.
Downloading web pages with curl is fairly easy, it gets a bit tricky though when you need to login to a web site before you can get to the web page you want to download...
Article Source Linux Journal
September 17, 2009, 9:49 am