Reverse signs of transactions in a qif file, and open it (OS X) in the associated program. My bank generates .qif files for my credit card with credit & debit reversed compared with how my finance program wants them.

fix-credit-card-qif.rb

#!/usr/bin/env ruby

require 'qif'

if ARGV.size != 1
  $stderr.puts "usage: fix-credit-card-qif-and-load.rb <CC qif file>"
end

input_filename  = ARGV[0]
output_filename = input_filename.sub(/\.qif/, "-fixed.qif")

input  = Qif::Reader.new(File.open(input_filename))

Qif::Writer.open(output_filename) do |output|
  input.each do |transaction|
    transaction.amount = -transaction.amount
    output << transaction
  end
end

`open #{output_filename}`