#!/bin/sh

# https://help.gnome.org/users/zenity/stable/progress.html.en

(
  echo "0" ; sleep 1
  echo "# Scanning mail logs..." ; sleep 1
  echo "10" ; sleep 1
  echo "# Updating mail logs" ; sleep 1
  echo "20" ; sleep 1
  echo "# Resetting cron jobs" ; sleep 1
  echo "50" ; sleep 1
  echo "This line will just be ignored" ; sleep 1
  echo "75" ; sleep 1
  echo "# Rebooting system" ; sleep 1
  echo "100" ; sleep 1
) |
zenity --progress \
  --title="Update System Logs" \
  --text="..." \
  --percentage=0

if [ "$?" = -1 ] ; then
  zenity --error \
    --text="Update canceled."
fi