Automatically change wallpaper randomly every X minutes.

auto_set_bg.sh

#!/bin/bash

export HOME=/home/shou
export BG_DIR="$HOME/Pictures/Anime/wallpapers"
export DISPLAY=':0'

rand_bg() {
    find "$BG_DIR" -iname "*.jpg" -o -iname "*.png" | shuf | head -n1
}

set_bg() {
    read bg_file
    feh --bg-fill "$bg_file"
    echo "$bg_file"
}

if [ -t 0 -o "$1" = "startup" ]; then
    rand_bg | set_bg
else
    set_bg
fi

crontab file

*/20  * * * *    root    test -x /home/shou/scripts/auto_set_bg.sh && /home/shou/scripts/auto_set_bg.sh startup