ftp_chmod() function in PHP

The ftp_chmod() function sets permissions on a remote file via FTP. This function allows you to modify file permissions on an FTP server using octal notation, similar to the Unix chmod command.

Syntax

ftp_chmod(connection, mode, filename)

Parameters

• connection − Required. The FTP connection resource

• mode − Required. The new permissions in octal format

  It consists of four digits −

  • The first digit is always zero

  • The second digit specifies permissions for the owner

  • The third digit specifies permissions for the owner's group

  • The fourth digit specifies permissions for everyone else

  Permission values (add numbers for multiple permissions) −

  • 4 = read permissions

  • 2 = write permissions

  • 1 = execute permissions

• filename − Required. The remote file to modify

Return Value

Returns the new file permissions on success, or FALSE on failure.

Common Permission Modes

Example

The following example demonstrates how to change file permissions on an FTP server −

<?php
    $ftp_server = "192.168.0.4";
    $ftp_user = "username";
    $ftp_pass = "password";
    $remote_file = "demo.txt";
    
    // Establish FTP connection
    $connection = ftp_connect($ftp_server);
    $login = ftp_login($connection, $ftp_user, $ftp_pass);
    
    if ($connection && $login) {
        // Change file permissions to 0755 (rwxr-xr-x)
        if (ftp_chmod($connection, 0755, $remote_file) !== false) {
            echo "Permissions changed successfully to 0755<br>";
        } else {
            echo "Failed to change permissions<br>";
        }
        
        // Change to read-only for all (0444)
        if (ftp_chmod($connection, 0444, $remote_file) !== false) {
            echo "File set to read-only (0444)<br>";
        }
    } else {
        echo "FTP connection failed<br>";
    }
    
    ftp_close($connection);
?>

Permissions changed successfully to 0755
File set to read-only (0444)

Conclusion

The ftp_chmod() function provides a simple way to modify file permissions on FTP servers. Always verify the connection before attempting to change permissions, and use appropriate octal values based on your security requirements.