bash_input.sh

#!/bin/bash
echo -n "Pick a color (blue, yellow, red ): "
read -e COLOR
echo It is a $COLOR day

interactive_example.rb

require 'open3'
puts 'top'
Open3.popen3('./bash_input.sh') do | stdin, stdout, stderr | 
  puts stdout.sysread(256)
  stdin.puts(gets())
end
puts 'bottom'

# top
# Pick a color (blue, yellow, red ): It is a hi day
# bottom