Controlling Terminal Cursor in Ruby

cursor.rb

class String
  def mv_up(n=1)
    cursor(self, "\033[#{n}A")
  end

  def mv_down(n=1)
    cursor(self, "\033[#{n}B")
  end

  def mv_fw(n=1)
    cursor(self, "\033[#{n}C")
  end

  def mv_bw(n=1)
    cursor(self, "\033[#{n}D")
  end

  def cls_upline
    cursor(self, "\e[K")
  end

  def cls
    # cursor(self, "\033[2J")
    cursor(self, "\e[H\e[2J")
  end

  def save_position
    cursor(self, "\033[s")
  end

  def restore_position
    cursor(self, "\033[u")
  end

  def cursor(text, position)
    "\r#{position}#{text}"
  end
end

Try that

#!/usr/bin/env ruby
class String

  def mv_up(n=1)
    cursor(self, "\033[#{n}A")
  end

  def mv_down(n=1)
    cursor(self, "\033[#{n}B")
  end

  def mv_fw(n=1)
    cursor(self, "\033[#{n}C")
  end

  def mv_bw(n=1)
    cursor(self, "\033[#{n}D")
  end

  def cls_upline
    cursor(self, "\e[K")
  end

  def cls
    # cursor(self, "\033[2J")
    cursor(self, "\e[H\e[2J")
  end

  def save_position
    cursor(self, "\033[s")
  end

  def restore_position
    cursor(self, "\033[u")
  end

  def cursor(text, position)
    "\r#{position}#{text}"
  end
end

#
# PoC
#
(1..3).map do |num|
  print "\rNumber: #{num}"
  sleep 0.7
  ('a'..'c').map do |char|
      print "Characters: #{char}".mv_down
      sleep 0.5
      ('A'..'C').map do |char1|
          print "Capital: #{char1}".mv_down
          sleep 0.2
          print "".mv_up
      end
      print "".mv_up
  end
  sleep 0.7
end
print "".mv_down 3