select-from


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#!/usr/bin/env ruby

require 'trollop'
require 'zipf'

opts = Trollop::options do
  banner "select_from [--invert] -i <file> < <line separated data>"
  opt :index,  "Line numbers to output.", :required => true
  opt :invert, "Invert selection.", :type => :bool, :short => '-j', :default => false
end

accept = {}

f = ReadFile.new ARGV[0]
f.readlines_strip.each { |line|
  accept[line.strip.to_i] = true
}

i = 0
while line = STDIN.gets
  if accept[i] && !opts[:invert]
    STDOUT.write line
  elsif !accept[i] && opts[:invert]
    STDOUT.write line
  end
  i += 1
end