Lock screen with gnome-screensaver-command схвати root (from/etc/pm/sleep.d рукописный шрифт)

My system (Ubuntu 15.10) ты существуешь в вирус: I have enabled "Require my password when waking from suspend" on the "Brightness и Lock" settings панель, but it does NOT ask for my password, which is incredibly insecure.

Схвати в workaround, гm trying to write в рукописный шрифт which will live under /etc/pm/sleep.d. It should be something like this:

#!/bin/bash

case "${1}" in
  hibernate)
    # Do nothing
    ;;
  resume|thaw)
    su -c "gnome-screensaver-command --lock" MYUSERNAME
    ;;
esac

Problem is, this doesn't work; the gnome-screensaver-command fails with the following message:

** Message: Failed to get session bus: Could not connect: Connection refused

Then, I tried to change the command to:

su MYUSERNAME -c "export $(dbus-launch) && gnome-screensaver-command -l"

Which then fails with:

** Message: Failed to get session bus: The connection is closed

So, the question is: what would be the right way to do this?