Example of using Notify OSD to display progress bar.

notify-osd-progress.sh

# Standard icons can be found in /usr/share/icons /usr/share/notify-osd/icons
seq 100 | while read number
do
  icon=$(( ${RANDOM: -1:1} + ${RANDOM: -1:1} + 1 ))
  icon=$(ls /usr/share/icons/gnome/32x32/emotes | grep face | sed s/.png// | head -n $icon | tail -n 1)
  notify-send -i $icon -h int:value:$number -h string:synchronous:my-progress "Progress"
  sleep 0.3
done

gdbus call --session \
  --dest org.freedesktop.Notifications \
  --object-path /org/freedesktop/Notifications \
  --method org.freedesktop.Notifications.Notify \
    my_app_name \
    42 \
    'utilities-terminal' \
    "Title $RANDOM" \
    'body' \
    '["action-name","Action"]' \
    '{}' \

exec 3< <(dbus-monitor --session --monitor "interface=org.freedesktop.Notifications")
while read type time sender _1 destination props
do
  eval $props
  if [ "$type" == "signal" -a "$interface" == "org.freedesktop.Notifications" ]
  then
    if [ "$member" == "ActionInvoked" ]
    then
      read type id <&3
      read type action <&3
      echo $id $action
    fi
    [ "$member" == "NotificationClosed" ] && break
  fi
done <&3