random wallpaper collection

#!/usr/bin/env bash
folder=$1
res=$2
list=$folder/list.txt
touch "$list"
for i in $(seq -f "%03g" 0 599); do
  while [ ! -f "$folder/$i.jpg" ]; do
    current=$(curl -si https://source.unsplash.com/random/$res | grep 'Location: ' | cut -d ' ' -f 2 | tr -d '[:space:]')
    found=false

    echo checking list for $current...

    while IFS= read -r line; do
      if [ "$line" == "$current" ]; then
        found=true
        break
      fi
    done < "$list"

    if [ "$found" == "false" ]; then
      echo file not found, downloading...
      curl -Lf -o "$folder/$i.jpg" $current && echo $current >> $list
    else
      echo file found, skipping...
    fi

    sleep 4
  done
done