How to add rel="canonical" link to section of Page

Hi,

I'm seeing a lot of duplicate content of my website in Google search results - multiple pages linked to same content like this: http://example.com http://example.com/page/1/ http://example.com/page/2/ etc all the page/ links shows the home page content ie. http://example.com since I set my home page as static.

I googled about this and found that setting rel=canonical will solve the issue. Can you please let me know the solution

The issue I was facing was the page rel="canonical" links were redirecting to a 404 page.

My rel canonical for page was "http://example.com/2/" instead of "http://example.com/page/2/" So I edited the rel canonical function in this file *wp-includes/link-template.php this file

function rel_canonical() {
  if ( ! is_singular() ) {
    return;
 }

 if ( ! $id = get_queried_object_id() ) {
    return;
 }

 $url = get_permalink( $id );

  $page = get_query_var( 'page' );
  if ( $page >= 2 ) {
   if ( 'page' == get_option( 'permalink_structure' ) ) {
      $url = add_query_arg( 'page', $page, $url );
    } else {
      $url = trailingslashit( $url ) . user_trailingslashit( $page, 'single_paged' );
   }
 }

 $cpage = get_query_var( 'cpage' );
  if ( $cpage ) {
   $url = get_comments_pagenum_link( $cpage );
 }
     echo '<link rel="canonical" href="' . esc_url( $url ) . "\" />\n";
}

I hard coded the home page url here for SEO and so now my page rank will flow to the home page now

$url = trailingslashit( http://example.com/ )

*for posts the rel="canonical" was working fine.

Hi Venkatesh,

You should definitely not make modification in WordPress Core files (Beans Core neither in fact) as it will be overwritten next time you update it. If you want to modify the WordPress Core rel_canonical(), you can do so by removing the action and re-add it with your own callback as follow:

// Remove WP Core action.
remove_action( 'wp_head', 'rel_canonical' );

// Add your own action callback.
add_action( 'wp_head', 'example_rel_canonical' );

function example_rel_canonical() {
 // Your modified code.
}

Hope that helps,

Thanks Thierry Muller for letting me know about that. I will remove the changes which I did and start using the child's functions.php