The simplest asciicast player

play.rb

# This plays asciicast (v1 format - https://github.com/asciinema/asciinema/blob/master/doc/asciicast-v1.md) in your terminal:
#   ruby play.rb asciicast.json

require 'json'

JSON.parse(File.read(ARGV[0]))['stdout'].each do |frame|
  sleep frame[0]
  STDOUT.write frame[1]
  STDOUT.flush
end