gistfile1.rb

require 'set'

GEM_FILE_TO_PROCESS = "Gemfile.lock"

def gem_list_finished?(line)
  line.include?("PLATFORMS")
end

def non_gem_line?(line)
  line.include?("GEM") ||
  line.include?("remote:") ||
  line.include?("specs:") ||
  line.empty?
end

def gem_name_without_version(line)
  line.split(' ').first
end

def get_files_in_gem(gem)
  #gem contents returns the files
  #as a line break delimited string
  `gem contents #{gem}`.split
end

def line_count_for_file(file)
  output = `wc -l #{file}`
  #line count is the first column from
  #the returned value
  output.strip.split(' ').first.to_i
end

def log(message)
  puts message
end

gemfile_list = File.read(GEM_FILE_TO_PROCESS)
gems_to_process = Set.new
total_line_count = 0

gemfile_list.each_line do |gem_line|
  gem_line = gem_line.strip
  break if gem_list_finished?(gem_line)
  next if non_gem_line?(gem_line)
  gems_to_process.add(gem_name_without_version(gem_line))
end

log "TOTAL GTP: #{gems_to_process.count}"

gems_to_process.each do |gem|
  log "Processing #{gem}"
  contents = get_files_in_gem(gem)
  gem_line_count = 0
  contents.each do |file|
    gem_line_count += line_count_for_file(file)
  end
  log "  LOC: #{gem_line_count}"
  total_line_count += gem_line_count
end

log "Total Lines: #{total_line_count}"

It should be noted that JB's post above was in response to version 2 of this Gist. The above version attempts to take into account better code principles, and I blogged about it at: Put Your Best Code Forward http://blog.coryfoy.com/2014/03/putting-your-best-code-forward/