How to set up an active desktop in 6 lines of Shell

I wrote this script to turn my desktop background into a live webcam view of Dublin, that would run all day long. The sun would slowly rise and set in my background, as I worked away in the foreground.

This illustrates the advantages of having a programmable system.

 url="http://images.ireland.com/webcam/liveview.jpg"
 file=dublin.jpg

 while true
 do
  lynx -reload -source $url > $file
  xv -root -quit -max $file
  sleep 1200
 done

Notes

• This was the Irish Times webcam (on their old domain ireland.com). The domain is sold and the webcam is gone.
• lynx is a command line browser. It can be used to make HTTP requests from scripts.
• xv is obsolete. This was used to set background image on X-windows systems. The command to do this in general depends on what GUI you are using. DCU Linux uses the GNOME GUI.
• sleep means sleep for this number of seconds (1200 = 20 mins)

• What happens if no "sleep" command?
• I say "6 lines of Shell" because it would be if you scrap the first 2 lines and hard-code the url and file.

• macOS introduced Dynamic Desktop in 2018. Set of images which are the same scene with different lighting for different times of day and night. OS changes image as day goes on.

Usage

• launch it in background: activedesktop &
• to find it: ps with options
• to stop it: kill PID
• or log off

To set background image in GNOME 3

   
 gsettings set org.gnome.desktop.background picture-uri "file://$file"

Notes:

• $file needs to be the absolute path of the file.

   
  gconftool-2   -t str   -s /desktop/gnome/background/picture_filename   $file
  gconftool-2   -t str   -s /desktop/gnome/background/picture_options    "stretched"