Clean JSON. Takes messy JSON and makes it much nicer looking. Use it with a json file passed in as a command-line argument or via standard input, thanks to the magic of Ruby's built-in 'json' library and pretty_generate

cleanjson.rb

# Clean JSON. Takes messy JSON and makes it much nicer looking.
#
# Usage:
#
#     ruby cleanjson.rb <infile> <outfile>
#
# Reads the JSON-formatted text in <infile> and outputs the cleaned JSON to
# <outfile>.
#
# Both arguments are optional, but you cannot specify an <outfile> without
# specifying an <infile>.
#
# You can use this with streaming input/output, such as:
#
#     cat file.json | ruby cleanjson.rb
#
# or
#
#     ruby cleanjson.rb <file.json >file_cleaned.json
#
# ...of course, the standard file-based syntax is 2 fewer characters to type
# than this.
#
# However, using this script as a pipe allows you to do nice things such as take
# messy JSON output from a script and pipe it through this to make it easier to
# read.
#
require 'json'

json_file, json_out_file = ARGV

json_text = nil

unless json_file.nil?
  if File.exist?(json_file)
    json_text = File.new(json_file, 'r').read
  else
    puts "File #{json_file} does not exist!"
    exit
  end
else
  json_text = $stdin.read
end

data = JSON.parse(json_text)

json_text = JSON.pretty_generate(data)

unless json_out_file.nil?
  f = File.new(json_out_file, 'w+')
  f.write(json_text)
  f.close
else
  $stdout.puts json_text
end