This is a little bash script I wrote to fetch the latest Sinfest webcomic and places it on my Gnome desktop. It also formats the image to scale on Sundays using ImageMagick.

UPDATE: as of 7 December 2009 this script is licensed GNU/GPL v2

#!/bin/bash
# fetch latest sinfest
# set as gnome desktop
# Copyright Jeff Channell 2009
 
# base url
URL=`echo "http://www.sinfest.net/comikaze/comics/"`
# name of file, based on date
FILENAME=`echo "`date +%Y-%m-%d`.gif"`
# where are we storing the images?
FOLDER=/home/jeff/Comics/sinfest/
# full path of file
LOCALFILE=`echo "$FOLDER$FILENAME"`
# check if storage exists...
file $FOLDER > /dev/null 2>&1
if [ $? -eq 1 ]
then
  # no folder, try to create
  mkdir -p $FOLDER
fi
cd $FOLDER
if [ $? -eq 1 ]
then
  # still no folder, die
  exit 1
fi
# go get the file
wget -nc $URL$FILENAME > /dev/null 2>&1
# check
file $LOCALFILE > /dev/null 2>&1
if [ $? -eq 0 ]
then
  if [ `date +%a` == "Sun" ]
  then
    # bonus - resize
    file `which mogrify` > /dev/null 2>&1
    if [ $? -eq 0 ]
    then
      mogrify -resize x970 "$LOCALFILE"
    fi
  fi
  # set background
  gconftool-2 --type string \
    --set /desktop/gnome/background/picture_filename "$LOCALFILE"
  gconftool-2 --type string \
    --set /desktop/gnome/background/picture_options "centered"
fi
exit 0

Then, to get it to run, I added this to my crontab:

0 */8 * *   *        /home/jeff/local/bin/desktop.bash > /dev/null 2>&1

UPDATE: I've been having some issues with cron not running lately as my user, but I also had Alarm Clock installed, so I just set a custom alarm to run my script there, and it's been working great ever since!