Usage:

dmvdostats
	[-h|--help]
	[-v|--verbose [-v|--verbose ...]]
	[--count <count>] [--interval <seconds>]
	[-o <fields>] [-O|--sort <sort_fields>]
	[-S|--select <selection>]
	[--noheadings] [--nosuffix] [--separator <separator>]
	[--units <units>]
	[<device>...]

<device> may be device name.
<fields> are comma-separated.  Use 'help -c' for list.