Issue `xscreensaver-command -lock` to all instances of xscreensaver
running on the host it's executed on, to which the user running this
script has permissions to access:

- If run as root, it will reach each and every instance of xscreensaver

- If run as a regular user, it will lock every xscreensaver of which this
  user can hold of the associated `XAUTHORITY` file, or if the host was
  added to the X server's host access list.

(C) 2024 Wolfgang 'datenwolf' Draxinger -- SPDX BSD-3-Clause