Commande ssh via php

<?php 

$host= '122.65.435.55'; 
$user= 'root'; 
$port= '22'; 
$password= 'root'; 
$con= 'null' 
function ssh($host, $user, $password, $command) 
{ 
    if (!function_exists("ssh2_connect")) die("function ssh2_connect doesn't exist"); 
    if(!($con = ssh2_connect($host, 22))){ 
        echo "échec connexion\n"; 
    } else { 
        if(!ssh2_auth_password($con, $user, $password)) { 
            echo "échec authentification\n"; 
        } else { 
            // execute a command 
            if (!($stream = ssh2_exec($con, $command ))) { 
                echo "échec de l'exécution de la commande\n"; 
            } else { 
                // collect returning data from command 
                stream_set_blocking($stream, true); 
                $data = ""; 
                while ($buf = fread($stream,4096)) { 
                    $data .= $buf; 
                } 
                fclose($stream); 
                return $data; 
            } 
        } 
    } 
} 

$command = 'php -m |grep ssh2'; 
$ret = ssh($host, $user, $password, $command); 
echo '<pre>' . $ret . '</pre>'; 

?>