[twinge]

Or use "kill -0 <pid>" to check if a signal can be sent/the pid exists.

[rahimnathwani]

Or use kill -USR1 <pid> to check the progress of dd

[DHowett]

Only if you've enabled it. If you've not, the process will terminate unceremoniously (in a mechanism borne entirely out of hatred for users.)

This is my favourite part of dd: The "will I receive a status report or will I terminate my long-running copy?" gamble.

[_ea1k]

Is that a BSD thing? I've never had to enable it on Linux to avoid killing the process.

[rahimnathwani]

Me neither, on debian.

[Freaky]

It's SIGINFO on the BSD's, and works with just about any process (though obviously not everything has a customized handler). Also handily mapped to Ctrl-T.