Quick script to scale retina images down 50% into a new file in current directory I also added a bash script in my /usr/local/bin so that I can run this from anywhere

unretina_it

#!/bin/bash
ruby ~/scripts/unretina_it.rb

unretina_it.rb

require 'RMagick'

Dir.new('.').each do |file|

  # Ignore hidden files
  if !file.start_with?(".")
    
    # Finds the file extension and file name without the extension (there is probably be an easier way but whatevs)
    start_extension = file.rindex(".")
    filename = file.slice(0, start_extension)
    extension = file.slice(start_extension, file.length - start_extension)
    
    # Finds only the filenames that are retina (ends with @2x)
    if filename.end_with?("@2x")
      
      # Removes the "@2x" from the filename for the unretina filename
      scaled_filename = filename.sub("@2x", "")
      
      # A puts you putz
      puts "Going to scale #{filename}#{extension} to #{scaled_filename}#{extension}"

      # Scales by 50% into new image (this probably overwrites if unretina already exists, I'm not sure though)
      img = Magick::Image::read( "#{filename}#{extension}" ).first
      thumb = img.scale(0.5)
      thumb.write "#{scaled_filename}#{extension}"

    end
  end

end