How to Find and Replace File Content on an FTP Server Using PHP

Preparation

Before starting, ensure you have a PHP environment with FTP extension enabled and the FTP server connection details (host, username, password, port).

Connect to FTP Server

Use ftp_connect() to create a connection, then ftp_login() to authenticate, and enable passive mode with ftp_pasv() . Example code:

// Set FTP server connection information
$ftp_server = 'ftp.example.com';
$ftp_user   = 'username';
$ftp_pass   = 'password';
$ftp_port   = 21;

// Establish FTP connection
$ftp_conn = ftp_connect($ftp_server, $ftp_port);
if (!$ftp_conn) {
    die("Unable to connect to FTP server");
}

// Login to FTP server
if (!ftp_login($ftp_conn, $ftp_user, $ftp_pass)) {
    die("FTP login failed");
}

// Set transfer mode to binary
ftp_pasv($ftp_conn, true);

Find Files and Replace Content

After connecting, list files in a remote directory with ftp_nlist() , download each file to a temporary local file, read its contents, replace the target string, write the modified content back, and upload the file using ftp_put() . Finally, delete the temporary file and close the connection. Example code:

// Set target strings
$old_string = 'example.com';
$new_string = 'example.net';

// Set remote directory
$remote_dir = '/path/to/remote/directory';

// List files in the directory
$file_list = ftp_nlist($ftp_conn, $remote_dir);

// Iterate over each file and replace content
foreach ($file_list as $file) {
    // Download file to a temporary local file
    $temp_file = tempnam(sys_get_temp_dir(), 'tempfile');
    ftp_get($ftp_conn, $temp_file, $file, FTP_BINARY);

    // Read file content
    $file_content = file_get_contents($temp_file);

    // Replace string
    $new_content = str_replace($old_string, $new_string, $file_content);

    // Write modified content back to server
    file_put_contents($temp_file, $new_content);
    ftp_put($ftp_conn, $file, $temp_file, FTP_BINARY);

    // Delete local temporary file
    unlink($temp_file);
}

// Close FTP connection
ftp_close($ftp_conn);

Conclusion

The article shows how to connect to an FTP server with PHP, retrieve a list of files, download each file, replace a specific string in its content, upload the updated file back to the server, and properly close the connection.