How to remove preview button programmatically

This is how you can remove the Preview button programmatically on all node forms in a form_alter hook.


<?php
//in form alter hook

       //Removes preview button on all node forms
    if(stripos($form_id, "node_form") > 0) {
      unset ($form['buttons']['preview']);
    }

//or a specific form...

        //Removes preview button on a specific form
    if(stripos($form_id, "[my-node-type]_node_form") > 0) {
      unset ($form['buttons']['preview']);
    }
?>

Knowledge keywords: 
Drupal 6.x
form_alter