figuring out what is using hw:0 question

[Tom Poe]

What command lets me figure out what is using hw:0 and not letting me 
set up QJackctl.  Here's output:
13:01:27.139 JACK was started with PID=2529 (0x9e1).
jackd 0.101.1
Copyright 2001-2005 Paul Davis and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver ..
apparent rate = 44100
creating alsa driver ... hw:0|hw:0|1024|2|44100|0|0|nomon|swmeter|-|32bit
control device hw:0
the playback device "hw:0" is already in use. Please stop the 
application using it and run JACK again
cannot load driver module alsa
13:01:27.341 MIDI connection change.
13:01:27.356 JACK was stopped successfully.
13:01:29.356 Could not connect to JACK server as client. Please check 
the messages window for more info.
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