a small script for a shell in shell. thanks to screenxtv gem and @grubrescue.

ptysh.rb

require 'io/console'
require 'pty'

PTY::getpty("sh") do |r,w|
  Thread.new do
    loop do
      w.write IO.console.getch
    end
  end
  loop do
    print r.readpartial 1024
  end
end