# Advanced filtering **URL:** https://community.mp3tag.de/t/advanced-filtering/16590 **Category:** Support **Created:** [February 11, 2015, 11:43am UTC](https://community.mp3tag.de/t/advanced-filtering/16590 "2015-02-11T11:43:25Z") **Posts on this page:** 1 **Showing post:** 15
### Author: ![DetlevD](https://community.mp3tag.de/user_avatar/community.mp3tag.de/detlevd/32/123_2.png) [@DetlevD](https://community.mp3tag.de/u/DetlevD) #### Post date: [February 14, 2015, 5:58pm UTC](https://community.mp3tag.de/t/advanced-filtering/16590/15 "2015-02-14T17:58:24Z")
> [@zerow](#): > > Let's break it down fo the dummies ... About Mp3tag Tools feature and examples of different tool configurations ... read there ... [/t/966/1](https://community.mp3tag.de/t/966/1) > [@zerow](#): > > What does this "$getEnv" will do? **$getEnv()** is a function call to the Windows operating system, in order to get the current content of a so called "environment variable". Using a well known "environment variable" has advantages in contrast to hard-coded paths and filenames. > [@zerow](#): > > For all selected files ... What happens with "yes"? Good question. Calling an application, which is made for invoking one file only, to be opened for multiple instances, ... all together at once, for example for ten or hundred or thousands of files, ... can make the computer system unusable for user intervention. DD.20150214.1958.CET --- _[View the full topic](https://community.mp3tag.de/t/advanced-filtering/16590)._