A Ruby script that just counts the number of lines in a given directory

linecount.rb

require 'pathname'

def count_lines(pathname)

  count = 0

  pathname.each_child do |child|

    if child.directory?
      count = count + count_lines(child)
    elsif child.file?
      count = count + %x{wc -l \"#{child.to_s}\"}.split.first.to_i
    end

  end

  count

end

if ARGV.length != 1

  puts "Error: invalid arguments"
  exit()

end

pathname = Pathname.new(ARGV[0])

if !pathname.exist? || !pathname.directory?

  puts "Error: directory not found"
  exit()

end

puts "Line count: #{count_lines(pathname)}"