Create a custom system message,is it doable?

[cogset]

Hi there,I was thinking if there's any way to create a custom-made system message (notification),like say the one popping up when the network goes up or down.
I was going to add a cronjob to rsync some directories on an external drive every day,only that drive won't be plugged in all the time,so a pop up message saying something like "cronjob starting in 5 minutes,plug in the drive" would be kinda handy
Can this be done in Gnome 2 ?

[scbingham]

motd (Message Of The Day) will display the contents of file /etc/motd when users log in.

wall (Warn ALL) will display the contents of a file to all logged in users. You could put this at the beginning of your script.

I used these commands in the pre GUI days of unix, so I'm sure there are prettier ways of doing something similar now.

[Lars Noodén]

Would zenity be of use? It provides a graphical popup.

DISPLAY=:.0. zenity --notification --text 'Hello, World'

[sudodus]

See this thread which uses notify-send

http://ubuntuforums.org/showthread.php?t=2115215

[cogset]

Would zenity be of use? It provides a graphical popup.

DISPLAY=:.0. zenity --notification --text 'Hello, World'

Oddly,zenity delivers only a tiny tooltip in the notification area (to see which you have to hover on the icon that pops up there) in Lucid with Gnome 2,but a nice full-sized notification balloon in Debian with Mate desktop.
From what I've read,looks like some people had such issues with zenity - maybe some extra libraries/packages are needed to have this notifications properly displayed?

EDIT: OTOH,after installing libnotify-bin as suggested in the next reply, and using notify-send,the notifications apparently work straight away from the command line.
Having them appear by means of a cronjob took more work,however:I ended up crafting a simple script like this

#!/bin/sh
/usr/bin/notify-send 'rsync cronjob starting IN 5 MINUTES :
PLUG IN USB Device ! '

and then adding this cronjob

DISPLAY=:0
30 08 * * * /home/user/script

following the directions in this article http://www.guyrutenberg.com/2012/08/...ion-from-cron/ -actually,many suggestions about how integrating messages with a crontab were too complicated for what I needed,this simple script (well just a cut and paste job,really ) does what I need.
Thanks for all the hints,BTW

[Habitual]

notify-send -t 10000 -u critical "cronjob starting in 5 minutes, plug in the drive"