If you are a user of BSNL’s DataOne Broadband service, run (don’t walk) to
Download, configure, be amazed, be very amazed.
In short, this is a script to capture and calculate your Dataone Usage from Dataone’s unhelpful Usage site.
Lots of options, well written. And excellent documentation included as well.
Kudos to Aravind SV – make sure to send him a thank you message.
I have only tried the Linux version. Gaurav tried the Windows version, and reports success as well.
Good stuff, and please note – it’s Free and Open Source Software (FOSS) 
BTW – I am being flooded with requests for help for Dataone setups. I’d love to help, guys, but I simply don’t have the time. You should *really* be going to VinuThomas.com and check out the forums there – lots of people, lots of help.