<?php
$fw=file('file.txt');
$post=implode(' ', $fw);
$content='content='.$post.'&copypaste=Проверка';

$url = "http://site.com/index.php";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url); // set url to post to
curl_setopt($ch, CURLOPT_FAILONERROR, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);// allow redirects
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); // return into a variable
curl_setopt($ch, CURLOPT_TIMEOUT, 3); // times out after 4s
curl_setopt($ch, CURLOPT_POST, 1); // set POST method
curl_setopt($ch, CURLOPT_POSTFIELDS, $content); // add POST fields
$result = curl_exec($ch); // run the whole process
curl_close($ch);
echo $result;
?>