rows2cols — transpose rows of text into columns, with custom separators. e.g. `rows2cols -c 3 -s ' '` will convert "foo\nbar\nbaz\nfoo\nbar\nbaz" to "foo bar baz\nfoo bar baz". Works on files and standard input

rows2cols

#!/usr/bin/env ruby

def run
  ARGF.each_slice($options[:columns]) do |values|
    puts values.map(&:chomp).join($options[:separator])
  end
end

require "optparse"

$options = { columns: 4, separator: " " }

OptionParser.new do |opts|
  opts.banner = "Usage: rows2cols [options] [file, file...]"

  opts.on("-c", "--columns N", Integer, "Number of columns") do |columns|
    $options[:columns] = columns
  end

  opts.on("-s", "--separator CHAR", "Separator character between columns") do |separator|
    $options[:separator] = separator
  end

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

run