[CentOS] Display a warning message at a certain time ?

Frank Cox a écrit :
> 
> On second thought, a bash file calling zenity in a cronjob will be
> better.  You can have zenity show any message you want in a window on
> the desktop and the only option available in that window can be "ok".
> kalarm would allow the user to change the alarm, and that's not what you
> want.

OK, I fiddled around with this, and here's what I got so far.

1) In an open GNOME session, when I launch GNOME terminal and type this:

$ zenity --info --text "Warning message!"

... I get exactly what I want.

2) When I put this line in a bash script (/usr/local/sbin/warning.sh) 
and launch it from within Gnome Terminal, I get the same result (as 
expected).

3) But when I add it to crontab like this :

# crontab -e

15 22 * * * /usr/local/sbin/warning.sh

... nothing happens at the given time (10:15 PM).

Any idea what's wrong here?