M_USAGE
#define M_USAGE "usage: devattr [-v] device [attribute [...]]"
#define M_USAGE "usage: devfree key [device [...]]"
#define M_USAGE "usage: devreserv [key [devicelist [...]]]"
#define M_USAGE "usage: getdev [-ae] [criterion [...]] [device [...]]"
#define M_USAGE "usage: getdgrp [-ael] [criterion [...]] [dgroup [...]]"
#define M_USAGE "usage: listdgrp dgroup"