#!/bin/sh
(
echo "10"; sleep 1
echo "# Mail logs are being updated"; sleep 1
echo "20"; sleep 1
echo "# cron-jobs are reset"; sleep 1
echo "50"; sleep 1
echo "This line is simply ignored"; sleep 1
echo "75"; sleep 1
echo "# system is restarting"; sleep 1
echo "100"; sleep 1
) | zenity --progress \
  --title="Update system logs" \
  --text="Mail logs are read ..." \
  --percentage=0