A script I modified for someone to randomise their Cinnamon wallpaper

cinnamon_rand_wallpaper

#!/bin/bash
# Script to set a per workspace desktop background in Cinnamon.
# Save as ~/bin/workspace_backgrounds_switcher.sh or 
# ~/.local/bin/workspace_backgrounds_switcher.sh and make executable
# Add an entry in startup applications to launch the script on start-up.

# Set path to background images
background_path=/usr/share/backgrounds/linuxmint/

# Select a random background from the aforementioned path
random_background=$(shuf -e "${background_path}/*" -n 1)

# Main script starts here
# Check for existing instances and kill them leaving current instance running
for PID in $(pidof -o %PPID -x "${0##*/}"); do
  (( "${PID}" != "$$" )) && kill -9 "${PID}"
done

# Monitor for workspace changes and set the background on change.
while read -r; do
  # Get the current background image
  current_background=$(gsettings get org.cinnamon.desktop.background picture-uri)
  # Ensure that our randomly selected background isn't currently in use
  while [[ "${current_background//\'/}" = "${random_background}" ]]; do
    random_background=$(shuf -e "${background_path}" -n 1)
  done
  gsettings set org.cinnamon.desktop.background picture-uri "file://${random_background}"
done < <(xprop -root -spy _NET_CURRENT_DESKTOP)