diff --git a/cards/_output/output.pdf b/cards/_output/output.pdf
index 430f5cd..8409e87 100644
Binary files a/cards/_output/output.pdf and b/cards/_output/output.pdf differ
diff --git a/cards/preprocess.rb b/cards/preprocess.rb
old mode 100644
new mode 100755
index 529d8e1..0aee383
--- a/cards/preprocess.rb
+++ b/cards/preprocess.rb
@@ -1,17 +1,60 @@
+#!/usr/bin/env ruby -w
 
-# input mode can be "txt" or "ods" 
-$input = "ods" 
+require 'optparse'
+require 'ostruct'
+require 'pp'
+require 'roo'
 
-# convert text files into .csv for deck.rb mogrification
-$cards_csv = "cards.csv"
+# command line options
+class Optparsec
+  # Return a structure describing the options.
+  def self.parse(args)
+    # The options specified on the command line will be collected in *options*.
+    # set default values here.
+    options = OpenStruct.new
+    options.input_file = "cards.ods"
+    options.output_file = "cards.csv"
+    options.input_type = "ods"
+    options.verbose = true
 
-# card descriptions in textfiles
-$cards_o = "cards-occasions.txt"
-$cards_q = "cards-qualifiers.txt"
-$cards_v = "cards-verbs.txt"
+    opt_parser = OptionParser.new do |opts|
+      opts.banner = "Usage: example.rb [options]"
+      opts.separator ""
+      opts.separator "Specific options:"
 
-# all card descriptions in a single spreadsheet
-$cards_ods = "cards.ods"
+      opts.on("-i", "--input FILE", "Input file") do |i|
+        options.input_file = i
+      end
+      opts.on("-o", "--output FILE", "Output file (csv)") do |i|
+        options.input_file = i
+      end
+      # type of input file (can also check extension)
+      opts.on("-t", "--type [TYPE]", ["ods", "csv", "txt"],
+            "Input type (ods, csv or txt)") do |t| 
+        options.input_type = t
+      end
+      opts.on("-v", "--[no-]verbose", "Verbosity") do |v|
+        options.verbose = v
+      end
+      # help and/or no opts
+      opts.on_tail("-h", "--help", "Show this message") do
+        puts opts
+        exit
+      end
+    end
+    opt_parser.parse!(args)
+    options
+  end  # parse()
+end  # class OptparseExample
+
+options = Optparsec.parse(ARGV)
+
+if options.verbose
+  puts "reading from file: " + options.input_file
+  puts "assuming input is: " + options.input_type
+  puts "results output to: " + options.output_file
+  puts "..."
+end
 
 # assuming an .ods file laid out as follows
 # 
@@ -19,7 +62,22 @@ $cards_ods = "cards.ods"
 # col 2 - qualifiers 
 # col 3 - verbs
 
-ods = Roo::OpenOffice.new($cards_ods)
+case options.input_type
+when "ods"
+  # all card descriptions in a single spreadsheet
+  ods = Roo::OpenOffice.new(options.input_file)
+when "txt"
+  # card descriptions in textfiles
+  $cards_o = "cards-occasions.txt"
+  $cards_q = "cards-qualifiers.txt"
+  $cards_v = "cards-verbs.txt"
+else
+  puts "input format not supported."
+  exit
+end
+
+# convert text files into .csv for deck.rb mogrification
+$cards_csv = options.output_file
 
 # preamble...
 File.open($cards_csv, "w")
@@ -40,18 +98,22 @@ def write_verb(line)
   File.write($cards_csv, "#{line},V,...,img/v_card.svg\n", mode: "a")
 end
 
-case $input
+# read descriptions and write to file...
+case options.input_type
 when "txt"
-  # read descriptions and write to file...
+  puts "reading descriptions from text files" if options.verbose
   File.foreach($cards_o) { |line| write_occasion line.chomp }
   File.foreach($cards_q) { |line| write_qualifier line.chomp }
   File.foreach($cards_v) { |line| write_verb line.chomp }
 when "ods"
-  # read descriptions and write to file...
+  puts "reading descriptions from ods file: " + options.input_file if options.verbose
   ods.column(1).each { |line| write_occasion line.chomp }
   ods.column(2).each { |line| write_qualifier line.chomp }
   ods.column(3).each { |line| write_verb line.chomp }
 else
   puts "input format not supported."
+  exit
 end
 
+puts "written out to file: " + options.output_file if options.verbose
+