$:.unshift '.'
$:.unshift './lib'
$:.unshift '../lib'

require 'open4'

#
# using block form process is automatically waited using waitpid2
#

out, err = nil

status =
  Open4::popen4('sh') do |cid, i, o, e|
    i.puts 'echo 42'
    i.close
    out = o.read
    err = e.read
  end

puts "out <#{ out.strip }>"
puts "err <#{ err.strip }>"
puts "status <#{ status.inspect }>"
puts "pid <#{ status.pid }>"
puts "exitstatus <#{ status.exitstatus }>"