ftp_cdup() function in PHP

The ftp_cdup() function in PHP changes the current directory to the parent directory on an FTP server. This is equivalent to the "cd .." command in Unix/Linux systems or "cd .." in Windows command prompt.

Syntax

ftp_cdup($ftp_connection)

Parameters

The function accepts the following parameter −

• ftp_connection − Required. The FTP connection resource returned by ftp_connect()

Return Value

The ftp_cdup() function returns TRUE on success or FALSE on failure.

Example

The following example demonstrates how to change the current directory to the parent directory −

<?php
    $ftp_server = "192.168.0.4";
    $ftp_user = "amit";
    $ftp_pass = "tywg61gh";
    
    // Establish FTP connection
    $con = ftp_connect($ftp_server);
    $res = ftp_login($con, $ftp_user, $ftp_pass);
    
    // Change to 'demo' directory
    ftp_chdir($con, 'demo');
    echo "Current directory: " . ftp_pwd($con) . "<br>";
    
    // Change to parent directory
    if (ftp_cdup($con)) {
        echo "Directory changed to parent!<br>";
    } else {
        echo "Directory change not successful!<br>";
    }
    
    echo "Current directory: " . ftp_pwd($con) . "<br>";
    
    // Close FTP connection
    ftp_close($con);
?>

The output of the above code would be −

Current directory: /demo
Directory changed to parent!
Current directory: /

Key Points

• The function only works if you have appropriate permissions to access the parent directory

• If already in the root directory, the function may return FALSE depending on the FTP server configuration

• Always check the return value to handle failures gracefully

Conclusion

The ftp_cdup() function provides a simple way to navigate up one level in the directory structure of an FTP server. Always verify the operation's success using the return value before proceeding with other FTP operations.