#!/usr/bin/ruby
# Original credits to Geet Duggal
# Concatenates an arbitrary number of files together into columns
# Columns map to lines in each file.
# Requirement: Files be of the same length.
# Oh, and cheers!
require "pp"
 
filez = ARGV.map do |fname|
  begin
    File.open(fname)
  rescue
    puts $!
    exit
  end
end
 
# Make sure all files have the same number of lines
num_lines = 0
num_lines = filez.map{ |f| f.readlines.length }.uniq
filez.each{|f| f.rewind }
if num_lines.length == 1
    num_lines = num_lines[0]
else
    puts "All files need to have the same number of lines"
    Process.exit(1)
end
 
# Go ahead and actually perform concatenation
while num_lines > 0
    puts filez.map{ |file| file.readline.chomp.split("\t") }.flatten.join("\t")
    num_lines -= 1
end