Drupal Customization - Add New tab to a page

In a Drupal content page, when the user is logged in, on the top of the page there are "View" and "Edit" link buttons for the user to view and edit the content of the page. Now we want to add a "New" link button to allow the user create a new page of this type. This can be done this way.

In "themes -> [theme folder] -> page.tpl.php", we have these two lines:

<?php if ($title): print '<h2'. ($tabs ? ' class="with-tabs"' : '') .'>'. $title .'</h2>'; endif; ?>
<?php if ($tabs): print '<ul class="tabs primary">'. $tabs . '</ul></div>'; endif; ?>

The first line is for the title. The second line is for the tabs "View" and "Edit". So we change the second line to be:

<?php if ($tabs): print '<ul class="tabs primary">'. $tabs . print_custom_tab($node) . '</ul></div>'; endif; ?>

And define the print_custom_tab() function at the end of the page:

<?php
function print_custom_tab($node) {
  // Use this to limit the "New" tab to certain page types.
  //if (substr($node->type, 0) == "[page type name]") 
  {
    return "<li><a href='?q=node/add/" . str_replace("_", "-", $node->type) . "'>New</a></li>";
  }
}
?>

From the $node we can also get $node->uid and other variables associated with node, and can do many other things this way.

Alternatively or in a cleaner way, there is an Add another module that do this. It needs to be configured on what page type and when to show. The configuration is done in "Administer -> Site configuration -> Add another".