Dear Sir or Madam,
I have been using a program called notify-send in scripts. Most commonly like so:
notify-send -u critical -t 0 'The process is DONE!' 'Check /mnt/BACKUPS/0day for a list of new items' | sndfile-play /usr/share/sounds/gnome/default/alerts/bark.ogg
I also enjoy having the desktop notification "bark" at me as well; thus, the addition of the pipe to sndfile-play and a moment of happy recollection of a puppy named Fluffy.
notify-send is found in the libnotify (rpm) or libnotify-bin (deb) package.
Yours with fond regards,