POINT A - sendfile.php

<?php 
$postdata = 'file='.urlencode(file_get_contents('filetosend.txt')); 
system('wget --post-data "'.$postdata.'" http://localhost/otherfile.php') 
?>

According to that script the file contents of filetosend.txt are transferred VIA http post to http://localhost/otherfile.php

POINT B - otherfile.php

<?php
if (isset($_POST['file'])) {
    file_put_contents('savehere.txt', $_POST['file']);
}
?>

According to that script the file contents are resaved in savehere.txt