Neural Networks (Prisma style) Video Processing Bash Script

#!/bin/sh
# This script takes multiple png from its folder and processes them via neural style:
# https://github.com/jcjohnson/neural-style
# This WILL take long time

# PLEASE TOUCH THESE SETTINGS

si="source.jpg"  # Source image (style to take from)
output=".png"    # Target extension
folder="mars"    # Working folder
be="clnn"        # Backend: clnn (opencl), cunn (cuda), nn (other)
iter="1000"      # Number of iterations (100 on Radeon RX470 tooks 15~25 seconds approx, default 1000)
directory="out"  # Result directory

# DO NOT TOUCH LOWER!
x=$(ls $folder/*png | wc -l)
mkdir $folder/$directory
for (( i=1; i<=$x; i++ )); do
lz=$(printf "%04d" $i)
time th neural_style.lua -style_image $folder/$si -content_image $folder/output_$lz.png -backend $be -num_iterations $iter -output_image $folder/$directory/frame$lz$output
done