'print render($content['links']);'
The links it is referring to are the comment links, statistics links and translation links of a node. 

So in a situation where you want just the comment links, it would be 

print render($content['links']['comment']);


For more information, see this page.

https://api.drupal.org/api/drupal/includes%21common.inc/function/drupal_pre_render_links/7