get_by_name.php

<?php
// script to remove categories from navigation menu

// $children = Mage::getModel('catalog/category')->getCategories(7);
  require_once 'app/Mage.php';
  Mage::app();
  
$category = Mage::getResourceModel("catalog/category_collection")->addFieldToFilter("name" , "Aphex Twin");
$cat_det=$category->getData();
$category_id=$cat_det[0][entity_id];
echo $category_id;