Randomly change desktop wallpaper on Gnome desktop

Below is the script to change the desktop wallpaper. The images are assumed to be in $HOME/wallpapers directory:

Just add that entry to the user crontab to change the wallpaper every hour (with the command crontab -e):

0 * * * * sh /PATH/TO/SCRIPT/random_wallpaper.sh

If you get the following error message:

(process:21381): dconf-WARNING **: failed to commit changes to dconf: Cannot autolaunch D-Bus without X11 $DISPLAY

Just add that line to your crontab:

DISPLAY=:0

This line tell cron that the display it requires to run the windowed applications is found at 0. (see http://www.codecoffee.com/tipsforlinux/articles/23.html)