Displaying Text on Remote Desktop over SSH

I used this trick to warn my kids that their computer playing time is almost over. The application name is zenity, and we need to set our DISPLAY environment to :0 beforehand so that the message will appear on their screen.

1. ssh into the machine

$ ssh foo@machine

2. Set the DISPLAY environment

$ export DISPLAY=:0

3. Use zenity to prompt messages to their screen. In this case, I use warning style message, and will be displayed for 2 seconds

$ zenity --warning --timeout=2 --text="Computer will be shut down in 15 minutes"