What is VQMod?
The way Opencart works, there was the need to manipulate files without direct editing. 2011 a developer created a new tool, called VQMod.
The idea behind is to create external files - based on XML - and change the desired scripts on-the-fly without editing manually the file itself.
This way every script - except files in the root (like index.php) as well as external CSS and Javascript files - can be changed in a very easy and simple way without any further knowledge of the system itself or coding.
VQMod has a neat side-effect: all changed files are cached and will be created new after a defined time (usually 60 seconds).
How to use?
Before these xml-files can be used, VQMod itself has to be installed. This is done by simply copy the files on the server and call once the installer which will prepare the system.
Then a simple copying of the xml-file into the correct folder (so called xml) and the rest of the work will be done automatically by the system.
What if I do not want to use VQMod but need the changes?
Well basically no problem, in this case the code is available inside the xml-file and changes have to be done manually.
What if I do not need VQMod anymore?
This a task for people who know how to edit files. Because the changes the VQMod installation has made, have to reverted.
What if I do not need the changes/modifcations (inside the xml-file)?
Either simply delete the file or rename it to something.xml_ (note the underline at the end). This will indicate the system that this file shall not be used furthermore. This can be done also by the VQMod-Manager.
How can I manage the VQMod-files (.xml)?
There is a tool called VQMod-Manager.