From Billstron

This simple project was inspired by a post on Lifehacker. The idea is to have a dynamic background image of the world changing from day to night. It should work with any distribution of Linux.

Instructions

The script is very simple. It just uses wget to get the picture from http://www.opentopia.com. It does check to make sure the file was downloaded so that if you are working off-line (heaven forbid) you keep the last downloaded image.

#!/bin/bash
# Where you want the images stored.  
WORKING="/home/bill/Pictures/wallpaper";

# Change directories to the working directory. 
cd $WORKING;

# Move the old one over if it exists
if [ -e $WORKING/world_sunlight_map_rectangular.jpg ]; then #File is there
	mv $WORKING/world_sunlight_map_rectangular.jpg   \
		$WORKING/world_sunlight_map_rectangular_old.jpg ;
fi
	
# Get the background image of the day/night world.
wget http://www.opentopia.com/images/cams/world_sunlight_map_rectangular.jpg  \
	-o $WORKING/log.txt -T 10 ;

# If it wasn't retrieved, move the old one back
if [ ! -f $WORKING/world_sunlight_map_rectangular.jpg ]; then #File is there
	mv $WORKING/world_sunlight_map_rectangular_old.jpg   \
		$WORKING/world_sunlight_map_rectangular.jpg ;
fi

# Set the image as the background.  
gconftool-2 --type string --set   \
	/desktop/gnome/background/picture_filename  \
	$WORKING/world_sunlight_map_rectangular.jpg ;</nowiki>

1. Download it here, and put it someplace in your home folder. In step 3 I will call this place [path to script].
2. Modify the WORKING variable to point to the location that you want to download the images to.
3. Set the cron job:

>> crontab -e
05 * * * * [path to script]/background_rotate.sh