#!/bin/bash

_LINES=$(ps -eo pid,cmd | grep wallpaper | \
  grep -v grep | grep -v $$ | awk '{print $1}' | tr '\n' ' ')

for i in $_LINES
do
  kill $i
done

while (( $(pgrep i3) ))
do
  feh --randomize --bg-max /usr/local/share/wallpapers
  sleep 10
done