PHP script to decode a Base64 string from a file

convert.php

<?php

// Note: this script was written just for testing
// purposes. It has no error checking and other
// controls. DO NOT RUN THIS COMMAND WITHOUT
// REDIRECTING THE OUTPUT TO A FILE, e.g.,
// convert.php mystring.txt > out.png

// open the file
$handler = fopen($argv[1], 'r');

// fetch the contents
$data = fread($handler, filesize($argv[1]));

// close the file
fclose($handler);

// decode the contents and print
echo base64_decode($data);
?>