title: Shell script changing desktop wallpaper
body: <p>Could you write the easiest possible shell script that will change the desktop wallpaper (in Ubuntu) in regular intervals (e.g. 1 minute).</p>
  
  <p>Wallpapers will be saved in particular directory (e.g. $HOME/wallpapers).
  I need only basic functionality.</p>
  
  <p>1) select random wallpaper from <code>$HOME/wallpapers</code><br>
  2) set it as wallpaper on desktop<br>
  3) set cron to run the script every minute (not part of the question).</p>