Copies pdf files from one directory into an other and removes on the fly the password from the pdf files that is requested to open them.

remove-passwords-from-pdf-files.rb

# Script using [qpdf](http://qpdf.sourceforge.net/) to
# remove the password from all pdf files in a given
# directory and its subdirectories.
# 
# Install qpdf with brew
# 
#     brew install qpdf
# 
require 'fileutils'

DIR = './pdf'
OUT = "#{DIR}-decrypt"

PASSWORD = 'THE PASSWORD'

base = Pathname.new(DIR)
pdfs = Dir.glob("#{base}/**/*.pdf")

if pdfs.size > 0
  puts "processing #{pdfs.size} pdf files"
  
  pdfs.each do |path|
    input = Pathname.new(path)
    out   = Pathname.new(File.join(OUT, input.relative_path_from(base)))
    
    FileUtils.mkdir_p(out.dirname, :mode => 0755) unless Dir.exist?(out.dirname)
    
    puts "decrypting #{input.relative_path_from(base)}"
    puts "  -> #{out.relative_path_from(base)}\n"
    
    `qpdf --password="#{PASSWORD}" --decrypt "#{input}" "#{out}"`
    
    if $?.success?
      puts '     done'
    else
      FileUtils.copy_file(input, out)
    end
  end
  
  puts "processed #{pdfs.size} pdf files"
end