Organize wallpapers according to aspect ratio

ratio_organizer.sh

#!/bin/bash
shopt -s nullglob # won't error if a glob has no match

wallpaper_dir="$HOME/Dropbox/Photos/Wallpapers"
cd $wallpaper_dir

files=(*jpg *jpeg *png *bmp)

for file in "${files[@]}"
do  read -r width height <<< $(sips -g pixelWidth -g pixelHeight "$file" | awk '/pixel(Width|Height)/ {print $2}')

    # Check if the file is a valid image, if not skip
    [ -z "$width" ] && continue

    # Test the ratio against my pre configured ones
    case $(echo "scale=3;$width / $height" | bc) in
        1.333) ratio="4:3" ;;
        1.250) ratio="5:4" ;;
        1.777) ratio="16:9" ;;
        1.600) ratio="16:10" ;;
        *) ratio="other_ratio" ;;
    esac
    
    echo "Moving $file to $ratio"
    mv "$file" "$wallpaper_dir/${ratio/:/x}/"
done