Redirect any WordPress attachment page to the actual file

redirect_attachment_page_to_file.php

<?php
/**
 * Redirect all attachment pages to actual file
 */
function redirect_attachment_pages() {
	
	global $post;

	// Return if not an attachment
	if ( !is_attachment() ) {
		return;
	}
	
	if( is_attachment() ) {
		$url = wp_get_attachment_url($post->ID);
		wp_redirect( $url, 301 );
		exit();
	}
}
add_action( 'template_redirect', 'redirect_attachment_pages' );