Important operatinol functions of Magento

1.How to get the category url in magento

<?php echo Mage::getModel('catalog/category')->load($catId)->getUrl() ?>

2.How to remove .html at the end of the url in magento
System => Configuration => Catalog => Search Engine Optimization and empty the fields "Product URL Suffix" and "Category URL Suffix"
3.How to get category’s Thumbnail image in magento

<?php $thumbnail=Mage::getModel('catalog/category')->load($categoryId)->getThumbnail();  //$category_Id -category id ,$thumbnail – image name
if($thumbnail !=''){
$imgPath = Mage::getBaseUrl('media').'catalog/category/'  // Get category image path
echo '';
?>

4.How to get Customer Details By Session

<?php  $customer = Mage::getSingleton('customer/session')->getCustomer();
    print_r($customer);?>

4.1How to get Customer Details By E-Mail

<?php   $customer = Mage::getModel('customer/customer')->loadByEmail(example@mail.com);
    print_r($customer); ?>

5.How to delete product by sku :-

<?php  $product = Mage::getModel('catalog/product');
   $productId = intval($product2->getIdBySku('putSkuHere');
   $product->load($productId)->delete(); ?>

6.How to get module table :-

<?php  
$resource = Mage::getSingleton('core/resource');
$tableName = $resource->getTableName('mymodule/mymodel') 
?>

how to upload any file in magento

Step 1 :- cretae html form for upload file

Upload File

                     

Step 2 :- Write Script for upload file

<?php

if(isset($_FILES['myfilename']['name']) && $_FILES['myfilename']['name'] != '')
{  
try
    {      
        $path = Mage::getBaseDir('media') . DS . 'csvfile' . DS;  //desitnation directory    
        $fname = $_FILES['myfilename']['name']; //file name
  $filpath = $path.$fname;
        $uploader = new Varien_File_Uploader('myfilename'); //load class
        $uploader->setAllowedExtensions(array('xls','xlsx','csv')); //Allowed extension for file
        $uploader->setAllowCreateFolders(true); //for creating the directory if not exists
        $uploader->setAllowRenameFiles(false); //if true, uploaded file's name will be changed, if file with the same name already exists directory.
        $uploader->setFilesDispersion(false);
        $uploader->save($path,$fname); //save the file on the specified path
    }
    catch (Exception $e)
    {
        echo 'Error Message: '.$e->getMessage();
    }
}
?>

How to create category from csv file

How to create bulk parent and sub category from csv file
Instruction:- Copy and save this code file in root folder of Magento and run it. exp :- http://yoursite/cat.php

<?php
error_reporting(E_ALL | E_STRICT);
$mageFilename = 'app/Mage.php';
require_once $mageFilename;
$app = Mage::app('admin'); 
Mage::setIsDeveloperMode(true);
ini_set('display_errors', 1);
ini_set('max_execution_time', 1800);
umask(0);
/************ Get CSV file **************/
  $path = Mage::getBaseDir('media') . DS . 'catcsvfile'; //file path of csv
  $files = glob($path.'/*'); // get all file names
  if($files){
   foreach($files as $file){ // iterate files   
     $csv  =  new Varien_File_Csv();
     $data =  $csv->getData($file); //path to csv
        }  
 array_shift($data);
 foreach($data as $_data){
/*****************  Prent category creation *****************/
   /*****************  Prent category creation *****************/
   $Pcat =  utf8_encode($_data[0]); // column to create parent category
   $getcategory = Mage::getResourceModel('catalog/category_collection')->addFieldToFilter('name',$Pcat);
   $catData = $getcategory->getData();
   $catcount  = count($catData);
    if($catcount==0 && !empty($Pcat))
   {  $category = Mage::getModel('catalog/category');
     $category->setName($Pcat);
     $category->setUrlKey($Pcat);
     $category->setMetaTitle($Pcat);
     $category->setIsActive(1);
     $category->setDisplayMode('PRODUCTS');
     $category->setIsAnchor(1); //for active achor
     $category->setStoreId(Mage::app()->getStore()->getId());
     $parentCategory = Mage::getModel('catalog/category')->load(2);
     $category->setPath($parentCategory->getPath());
     $category->save();
  }
/*    Child category creation             **********************/
   global $childcat;
    $childcat = utf8_encode($_data[1]); // column to create sub category
   $pgetcategory = Mage::getResourceModel('catalog/category_collection')->addFieldToFilter('name',$childcat);
   $pcatData = $pgetcategory->getData();
   if(!$pcatData) {
    $getcategory2 = Mage::getResourceModel('catalog/category_collection')->addFieldToFilter('name',$Pcat);
    $catData2 = array();
   $catData2 = $getcategory2->getData();
   if(!empty($catData2)){
   $ParentCategoryId2 = $catData2[0]['entity_id'];   
     $category = Mage::getModel('catalog/category');
     $category->setName($childcat);
     $category->setUrlKey($childcat);
     $category->setMetaTitle($childcat);
     $category->setIsActive(1);
     $category->setDisplayMode('PRODUCTS');
     $category->setIsAnchor(1); //for active achor
     $category->setStoreId(Mage::app()->getStore()->getId());
     $parentCategory = Mage::getModel('catalog/category')->load($ParentCategoryId2);
     $category->setPath($parentCategory->getPath());
     $category->save();
   }  
   }
 }
}
else
{
echo 'file not found';
}
?>

How to get category id by category name in magento

<?php
$category = Mage::getResourceModel('catalog/category_collection')->addFieldToFilter('name','cateNameHere'));
    $catData = $category->getData();      
 $categoryId = $catData[0][entity_id];
 echo $categoryId;
 ?>

How to delete all category in magento

Instruction :- Copy and save this code file in root folder of Magento and run it; exp :- http://yoursite/deletecat.php

<?php 
error_reporting(E_ALL | E_STRICT);
$mageFilename = 'app/Mage.php';
require_once $mageFilename;
Mage::setIsDeveloperMode(true);
ini_set('display_errors', 1);
ini_set('max_execution_time', 1800);
umask(0);
Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);
foreach(Mage::getModel('catalog/category')
->getCollection()
->addFieldToFilter('entity_id', array('gt' => 2)) as $cat) {
$cat->delete();
}
?>