
  bty __BTY_VERSION__ live env

  CLI:        bty --help
  TUI:        bty-tui
  Mounted:    /var/lib/bty/images   (BTY_IMAGES exFAT, RO in live env)
  Logs:       journalctl -u bty-flash-on-boot
              journalctl -u bty-tui-on-tty1

  This rootfs is a read-only squashfs with a tmpfs overlay -- any
  changes vanish on reboot. Files dropped onto BTY_IMAGES from
  another host persist on the stick.

