title: Append array to existing json file without loading and decoding the hole file
body: <p>I´m creating a txt file importer using php, wich can be quite large reaching about 150MB in the near future, what i´ve done is divide the import process in a few steps, and in one of them a save the data extracted from the txt to a new json file.
  What i like to do is append a new json encoded array to this file in each loop, avoiding having a very big array after 80MB processed and save everything at once, can anyone tell me how insert a new json encoded array into a existing json file without loading the hole file, decode it insert to the array and encode it again ? this could save a lots of resources in my inporter, i´ve searched trough out the site, but did not find anything like this.</p>