I was thinking about the default comma formatting. Right now it does this:

$ ./bcalc '2*1000000000'
2,000,000,000

But there are other countries with other number formatting traditions. For example I found this article showing some of them. It would be great if this formatting can be specified.

I'm not sure what would be the best way to do it. I was hoping if it was possible to specify the format with an arg like ###,###,###.##. Another way would probably be to mention the country codes.