Use the below command :

rm -rf lampp

It deletes all files and folders contained in the lampp directory.

In case user doesn’t have the permission to delete the folder: Add sudo at the beginning of the command :

sudo rm -rf folderName

Otherwise, without sudo you will be returned permission denied. And it’s a good practice to try not to use -f while deleting a directory:

sudo rm -r folderName

FYI: you can use letters -f, -r, -v:

-f = to ignore non-existent files, never prompt
-r = to remove directories and their contents recursively
-v = to explain what is being done