XFCE - Screen lock using LightGDM

PATH=/bin:/usr/bin
export PATH
# Lock by xscreensaver or gnome-screensaver, if a respective daemon is running
#for lock_cmd in \
#    "xscreensaver-command -lock" \
#    "gnome-screensaver-command --lock"
#do
#    $lock_cmd >/dev/null 2>&1 && exit
#done
for lock_cmd in \
    "dm-tool lock"
do
    $lock_cmd >/dev/null 2>&1 && exit
done
# else run another access locking utility, if installed
for lock_cmd in \