Stupid implementation of the unix tool wc in Ruby

wc.rb

#!/usr/bin/env ruby

require 'optparse'

options = {}

# parse commandline options
OptionParser.new do |opts|
  opts.banner = "Usage: #{__FILE__} [-lmw] [file]"

  opts.on('-l', '--lines', 'The number of lines in input file') do
    options[:lines] = true
  end

  opts.on('-w', '--words', 'The number of words in input file') do
    options[:words] = true
  end

  opts.on('-m', '--chars', 'The number of bytes in input file') do
    options[:chars] = true
  end

  opts.on( '-h', '--help', 'Display this screen' ) do
    puts opts
    exit
  end
end.parse!

# output all values if no option is given
if options.empty?
  options = {
    :lines => true,
    :words => true,
    :chars => true
  }
end

file_name = ARGV.last
content = ""

# read from stdin (pipe) if no file is given
if file_name
  content = IO.read(file_name)
else
  content = ARGF.read
end

# calulate metrics
options.each do |key, value|
  case key
  when :lines
    print "\t#{content.split(/\n/).length}"
  when :words
    print "\t#{content.split(/\s/).length}"
  when :chars
    print "\t#{content.length}"
  end
end
print "\t#{file_name}" if file_name
print "\n"

Here is another implementation via Ruby 2.0 and its feature Enumerator#lazy