On BSD (including Mac OS X), you can also type ^t at dd, and it will print status information. If that doesn't work, do stty status ^t first. This is SIGINFO;

On BSD (including Mac OS X), you can also type ^t at dd, and it will print status information. If that doesn't work, do stty status ^t first. This is SIGINFO; it's been in BSD for a long time, but isn't in Linux and is relatively unknown nowadays. Quite a few BSD command line programs will respond to it.