select-from


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#!/usr/bin/env ruby

require 'optimist'
require 'zipf'

opts = Optimist::options do
  banner "select_from [--invert] -i <file> < <line separated data>"
  opt :index,  "Line numbers to output.", :type => :string, :short => '-i', :required => true
  opt :invert, "Invert selection.", :type => :bool, :short => '-j', :default => false
  opt :from1,  "Index starting from 1.", :type => :bool, :short => '-k', :default => false
end

accept = {}
f = File.open  opts[:index]
f.each_line { |line|
  i = line.strip.to_i

  accept[i] = true
}

i=0
if opts[:from1]
  i = 1
end
while line = STDIN.gets
  if accept[i] && !opts[:invert]
    STDOUT.write line
  elsif !accept[i] && opts[:invert]
    STDOUT.write line
  end
  i += 1
end