Post file to server via php (cUrl)

curl_file_post.php

$ch = curl_init();
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, array('file' => '@/path/to/file.txt'));
curl_setopt($ch, CURLOPT_URL, 'http://server2/upload.php');
curl_exec($ch);