List attached USB devices in a script-parseable format.
$ git clone https://github.com/ushroo/openbsd-usbdevices.git
$ cd openbsd-usbdevices/
$ make
$ ./usbdevices
uhub0 EHCI root hub (Intel)
uhub2 Rate Matching Hub (Intel)
uhidev0 USB Keyboard (Logitech)
uhidev1 USB Keyboard (Logitech)
uhidev2 Gaming Mouse G400 (Logitech)
uhidev3 Gaming Mouse G400 (Logitech)
uhub1 EHCI root hub (Intel)
uhub3 Rate Matching Hub (Intel)
umodem1 Adafruit Industries (vendor 0x239a)
uhub4 4-Port USB 2.0 Hub (Generic)
urtw0 RTL8187 (Realtek)
umodem0 u-blox 7 - GPS/GNSS Receiver (u-blox AG - www.u-blox.com)