linux-wallpaperengine-kde/tools/run-over-all-backgrounds.sh

#!/bin/bash
if [ $# -eq 0 ]
  then
    echo "Please provide the current build's executable path. You might want to run this script off the same folder."
fi

# ensure the output and images directory exists
[ -d "output" ] || mkdir output

for folder in ~/.steam/steam/steamapps/workshop/content/431960/*; do
  # only directories matter
  if [ -d "$folder" ]; then
    bgid=$(basename "$folder")

    echo "Running wallpaperengine for background $bgid and waiting for it to finish"
    # run and wait for it to finish
    $1 $bgid
    # move output.webm to the output folder with the right name
    mv output.webm output/$bgid.webm
    # take a screenshot
    ffmpeg -ss 00:00:03 -i output/$bgid.webm -frames:v 1  output/$bgid.jpg
    # copy over the project.json so we have it on hand
    cp $folder/project.json output/$bgid.json
  fi
done