Takes a screenshot every 5 seconds and save the file to a certain folder passed as argument (works on OS X)

screenshots.rb

#!/usr/bin/env ruby

#
# Takes a screenshot every 5 seconds and save the file to a certain folder passed as argument.
# It uses screencapture, which comes with OS X.
#
#

require 'fileutils'
include FileUtils


def find_max_dir(path)
  max_dir = 0
  Dir.glob(path + '/*').each do |name|
    next unless File.directory?(name)
    next unless File.basename(name) =~ /^(\d+)$/
    value = $1.to_i
    max_dir = value if value > max_dir
  end
  max_dir += 1
  max_dir_name = '%04d' % max_dir

  path = File.join(path, max_dir_name)
  mkdir_p(path) unless File.exists?(path)
  puts "using directory #{max_dir_name}"

  path
end

def capture(path)
  index = 0
  wait_time = 5
  while true do
    print '.'

    name = File.join(path, '%07d.jpg' % index)
    if File.exists?(name)
      puts "\n#{File.basename(name)} already exists, overwriting"
      rm(name)
    end

    out = `screencapture -t jpg -x "#{name}" 2>&1`
    raise "error capturing: #{out}" unless $?.success?

    index += 1

    sleep wait_time
  end
end




path = ARGV.shift
if path.nil?
  puts "usage: #{$0} <capture_path>"
  exit 1
end


mkdir_p(path) unless File.exists?(path)
path = find_max_dir(path)
capture(path)