How can I know the Elo rating of my chess engine? I built an uci compatible chess engine, and I would like to know its Elo rating. What is the easiest way to get it?

I would like something that works both on Linux and Windows.
Easy question. Announce your engine on the chess programming forum (http://talkchess.com/forum/index.php). There'll be engine testers adding your engine to their rating list, such as CCRL. But please and please provide a working compiled binary.

Announce your engine, upload a compiled binary to somewhere like Dropbox. You'll hear feedback.

EDIT

cutechess is a popular tool for automating computer engine-to-engine matches. The only and only way to test your changes is to make your engine to play games. You can make it to play with an older version or another engine.

https://chessprogramming.wikispaces.com/Cutechess-cli