PHP | ftp_exec() function

<?php

// Connect to FTP server
// Use a correct ftp server
$ftp_server = "localhost";

// Use correct ftp username
$ftp_username="username";

// Use correct ftp password corresponding
// to the ftp username
$ftp_userpass="password";

// Command to be executed on FTP server
$command="ls-al > test.txt";
 
// Establishing ftp connection 
$ftp_connection = ftp_connect($ftp_server) 
        or die("Could not connect to $ftp_server");

if( $ftp_connection ) {
    echo "successfully connected to the ftp server!";
    
    // Logging in to established connection with
    // ftp username password
    $login = ftp_login($ftp_connection, $ftp_username, $ftp_userpass);
    
    if( $login ) {
        
        // Checking whether logged in successfully or not
        echo "<br>logged in successfully!";
        
        // ftp_exec() executes the command 
        if (ftp_exec($ftp_connection, $command)) {
            echo "<br>".$command." has been successfully executed.";
        }
        else {
            echo "<br>Error while executing the command .";
        }
    }
    else {
        echo "<br>login failed!";
    }
    
    // Closing  connection
    if(ftp_close($ftp_connection)) {
        echo "<br>Connection closed Successfully!";
    } 
}
?>